Yeah I understand Singer, it´s a bit of a dig into the wallet indeed. Tho here in sweden, the finished painted NSR cars usually go for 700-750 sek per car! The white kits you can get for 500-600 sek if you look around. Problem is that nobody here in sweden usually keep 5 of the same kit in stock so you have to order them and wait, and it can take a month or even more if you´re unlucky.
Check UK e-Bay if you can handle waiting a few weeks for delivery and you found someone with 5 equal cars in stock. I tend to order cars there, even with UK listprice i save 100-150 sek per car on NSR or Slot.IT with the shipping included.
Otherwise, my favorite swedish Slot Car dealer just got a bunch of white-kits delivered...
http://www.slotcar4fun.se/nsr-audi-r8-gt3-...-21k-rpm/3207-0
http://www.slotcar4fun.se/nsr-audi-r18-lms...21-k-rpm/3206-0
http://www.slotcar4fun.se/nsr-mosler-mt-90...ght-body/1472-0
(Hope I dont break a forum law now by posting links to a seller).
I dont think you will have any problems re-painting finished cars either, but I think it will be a bit of a fiddle to first take them apart. Some parts can be glued on for instance and might easilly carp up the paintjob if you leave them on and just try to mask them while repainting. So best would probably be to just strip the cars into neutrons, then go at the body. I am totally a beginner when it comes to these things, but I imagine you can get away with just priming up a body, sanding, spraying, masking, spraying.. and clear finish the bodies, even if they are already painted.
If you want to cheat a bit with the decals and company logo / theme, then check this out.
http://www.testors.com/product/136937/9203...Clear_%26_White
Basically you make your own decals using a simple ink-jet printer. Design your logo, print it, stick it on and put some finish on it. I planning to do this now myself with a white kit NSR where i cheat a bit. The base body will just be in two colors (since I´m a total noob with painting) and then the rest of the decoration will be printed using decals. Just be aware that you cant print white, so you need white decal paper if you want a white text/background.
With the chips... yep... digital costs more. Sad but true. I usually tell myself that it´s an investment since I can move them between cars... not sure I beleive myself yet...
Check UK e-bay there also, you can save a few DKr if you are lucky and can wait. Ironman has a good point, the Slot.IT white kits are a bit cheaper. I haven´t bought any of them myself yet, but Slot.It´s quality is next to noone, so I am sure their white kits are as wonderful as their finished cars.
Hope you post a few pics of the event when you´re done Singer, so I can send the link to MY boss...
[Edit]
I couldn´t help myself so i checked e-bay a bit. Here is a link to one of JadLam´s auctions, they are great sellers and I bet you can get a good price on 5 of these black windowed Scalextric cars with chip included if you e-mail them and ask. Last car I bought from them arrived in 5 days and they are easy to deal with and are open to combine shipping.
http://www.ebay.co.uk/itm/SCALEXTRIC-Digit...=item3a6e6a5a79
// Micke