I don't know if the vapor lock issue is common, i've done a google search and found a few people that had the same issue. Some people have said they've tuned it out of their engine, but I haven't been able to do that yet. The guy at my local hobby shop said a different carb with an insulator would fix the problem but Losi's carb is a weird size and the only one that would fit is a Picco. I've been thinking of putting a new pipe on it to possibly bring the temps down, mine runs at about 240, (which is normal for that engine/pipe combo from what i've read) and also upgrading to the turbo head.
The clutch is something I forgot to mention. The RTR only comes with 2 shoes so I did add a pair of composite shoes w/ green springs. I also had to buy the clutch hardware ($5) because either the kit didn't come with extra clutch pins or I misplaced them.