TomEG - I started off with just one build - kyosho scorpion with vintage scorcher body, I knew what I wanted and the design was so clear in my mind, started hopping it up with CRP axles, ishipla shocks, later alloy wheels, than CB like short shocks, mounted re-re body with cut out fenders so the tires don't bottom out on the fenders, looked like a true baja buggy, and yes gotta get those original baja bug license plate!! I am a sucker for vintage realistic parts - anything that is both functional and looks scale, love those to bits, I end up buying them and think of using them, where, well why not build another car, then you start thinking of putting more rare parts on it, thats how it starts. Its good when you are finishing your projects, I am not! I have 4 outstanding builds, 2 still ideas and in the pipeline, I have not spent so much, but enough, if I finish all up, the $$ is justified, I would not say I have an addiction - its passion baby! I'd rather be playing with RC then playing vid games, chatting on social media etc.
I hope you find a thorp diff, Hattrick, but be ready to spend $100+ for it, now that there are re-re scorps and what not from kyosho, and they are ALL GOOD with just a hint of modern twist for more fun and performance, thats not bad at all, you will find a vintage easily enough, sometimes you might have to buy a vintage roller that has the diff inside, etc, this is a secret, I am sure all know it, but if the half drive cups coming out of the gearbox is grayish silver, its most probably has a thorp in it, if blacj, its standard kyosho geared diff.
Here is some of my stuff - kyosho beetle, kyosho datsun truck, chevy gasser (still in the pipe lines), kyosho rowdy with ball diff!, optima mid etc and a bunch of cool vintage parts - shocks, ball joints etc
https://www.flickr.com/photos/110872915@N05/albums