Hi Macky
very nice OVA T4 my friend it looks very similar to my personal one i use for testing ect, all hop ups ect plus new style camber links, Graphite arms ect.
Your completely correct about the upper decks being 3mm and lower chassis being 2.5mm as option parts
The car is very fast and super robust, and a joy to work on.
I can understand you not wanting to harm the car because of it being in your very interesting collection.
We have been running cars with one ways, and also been using delrin diffs front and rear, plus new machined locked center oneways for very tight tracks
At the moment I have been running car with Novak Brushless when i can and for testing which gives me more track time.
Ive also machined and built T4 prototype 4wd Buggy ( which will not be but in to production) its more to show my companys machining standards ect but it does run very well.
Take care
Dan