Ok
I think if you have a 2000 series one it will be a chipped key [meaning it has a micro chip in it without which it will not start] any key is able to be cut and will work the doors but will not start it as it doesnt have the chip that tells the computer its the right keys etc effectively an immobiliser ......

As for your alarm sorry i am unable to help probably an after market one where is it fitted ie the box ??? for it maybe a picture might help ......

I hope this helps

My 2000 W plated 2.5tdi had chipped keys where as my 1999 1.9td doesnt £5 for a new key but still has a factory immobiliser when turned off and is there fore equally as safe in terms of being totally stolen.......

My new one is in build currently and is going to have a removable steering wheel fitted much like the GP cars of Grand Prix not to be wide nor smart nor fashion contious but to enable my drivers seats to totally swivel right around without which it wont and also what a deterrant to would be theives

I personaly don't rate car alarms, no body pays a blind bit of notice to a car horn going off these days seeing as how they are notoriously unstable. i wouldn't have one in mine at all however thats not to say i wouldn't have it secure there are many subtle ways of detering theives ours is getting high security door locks as fitted to cash in transit vans not cheap but makes the doors inpenetrable from outside along with shatterproof film on all windows except the front windscreen coz its illegal, added to a removable steering wheel and hidden safes i think it will be as safe as it can be without being armour plated and all windows screened much like a Police roit van....my personal choice as we like to wild camp which means it will have to be left in forrests etc unattended at times ....

All decent alarm manufacturers have websites on those websites is usually free downloadable wiring and user guides ..... Try that as a source to find out about your alarm buddy persoanlly i would pull it out or at least disconnect it...... some if fitted in fuse box area were fitted by VW when new i have yet to see one of your vinateg still working though.... my 2000 had one in that very location which when i bought it was all taped up non functioning which seems to be par for the course and even less likely if fitted under the bonnet to still be working nowadays ...

For reasons of security replacement keys are only available from Volkswagen dealers

Key Tag
The key tag contains the key number which is needed to obtain replacemnt keys Volkswagen dealers can ONLY order replacemnt keys if you have this number..

Electronic Immobiliser
The electronic immobiliser prevents unauthorised persons using your vehicle
The micro chip is located in the head of the key which automatically deactivates the immobilisers when the key is inserted in the ignition lock assembly.
The system is automatically activated when the ignition is switched off
Thus the engine can only be started with a correctly coded genuine Volkswagen key, troublefree operation of your vehicle can only be gaurenteed using genuine keys at all times...

NOTE
It has been known elsewhere to be able to avoid getting an expensive key cut at your local VW dealers when your original key breaks by removing the chip and affixing it to the new £5 shoe shop cut key, or by secretting the said chip somewhere close by the ignition barrel and simply using the new cheap cut key in the usual fashion, some say that it only has to be in close proximity to the barrel to work, others say it has to be touching it, i have personally tried all methods to th extent of taping the broken chipped key to the ignition barrel non of my methods worked so i deem this to be total fabricated nonesense possibly you might be lucky but beleive me when i say by leaving the chip full time in the vehicle you are making it in anycase so easy to steal making your insurance non invoid......

Word is certain branches of Timpsons and other key cutters are now coming into the 21st century and can indeed cut chipped keys if you know of one anywhere in the country do please let us know as £90 + the vat is just ridiculous a price to pay for a key...when i had mine i serachd endlessly and was unable to find a supplier at a reasonable cost maybe you know better??? that is one local enough to not require my only key to be sent to them for recutting a very dangerous system if you only hav eone besides i needed it so as to be able to drive it....so post away companies in my view were simply carrying to much of a risk....

Doing what we ended up doing having only the one chipped key at the end we got a £5 spare that locked and unlocked all doors glovebox etc and we used it to open and lock it with religiously whilst only ever using the chipped key to start her thus prolonging the life of our only chipped key at this point

I am glad i have now gotten a non chipped key version and rely on non electrical parts for my security that are far less likely to fail...

As for your keys they get broken, lost and such like its now 10 yrs old after all i mean what 10 yr old do you know that has not been lost at some stage.....

Your Alloys will possibly look good right now but quickly pit if not maintained and well loked after/cleaned costing fortunes to put right apart from costing a morgage to re-tyre as you rightly point out, again i swapped my lowered [60mm] and wide wheel tyred T4 for a bog standard version on 15 inch standard rims and tyres the important thing in the wheel and trye department is that they are rated over 92 and are VAN rated tyres you always use beware many will tell try to sell you anything that fits but insists on UPRATED VAN TYRES ALWAYS to stay safe and legal, as for alternatives mostly all VW and Audi Seat/Skoda alloys will fit form same age or newer versions of your van found online ebay or in secondhand wheel shops or for the cheapest option put yours up for sale with a free add here and sell them stating you will take x off if the buyer suppliues a set of standard wheels in deal as they will need to take theirs off to put yours on, as for a spare unless using standard wheels you are unlikely to get one as none fit in the cradle under your back door which is why you wont have one....jack and whell brace are usually behind drivers seat or underneath it, mine were parcelled up inside my spare in the whell cradle under the van.....

I am glad you like our site i can assure you it takes a lot to keep it running but its worth it none the less, if only to help poor souls like yourself...
I would love to add you to our "T4 Show Us Yours" and rolling image widget on our front pages an image or two then of your bus would be good,

Like the idea of your cooler maybe you could start a how to in the "How To Forum" and take us through how you built it and what you needed to build it along with a few images as you go, might spur some of us on to copy it, personally the window down will do me but then i dont have dogs [i did so can empathise]

As for your central locking my views are if its not factory fitted DONT BOTHER its more hassle than its worth and very often is besides its just another electrical item to go wrong really..
[Says the owner [me] who sold his 2.5tdi in favour of the lesser complicated 1.9td and most certainly do not regret it not one little bit]

Already been done, see link below.;)

http://www.instructables.com/id....d-easy!