Well, received my 501X yesterday and it was mostly built in 3 hours (BAR the electronics, but they're not going in before next week anyway). What took me longest was to get all the air bubbles out of the shocks, lol.
As for the screws, I tried tightening the first screw like normal and unscrewing it, and i stripped it
. However the fault isn't the screw's but the C/F of the chassis. I noticed that the chassis squeals when you tighten a screw. So what I did is do it by steps, tighten reasonably gently, unscrew, and so on until the screw isn't as hard to unscrew and it works. You'll notice that at every step you'll be able to screw the screw a tad more, like 1/8th of a turn more. I think this is due to the C/F compressing a bit. I have to say it has never happened to me with Tamiya, and it could simply be that batch of c/f that is like that.
Now I have to get the fooked screw out but all the others are easy to get off
.
Another point, I've never seen a kit with so many screws. It might be worth getting a complete set of Ti / Aluminium screws and save a fair amount of weight.