I wonder if the truck you're looking at buying is an Aftershock. They came w/ the Mach-26, and IIRC they are basically the same truck as the original LST. In which case, no, it's probably not a good idea to pay 400 bucks for a used truck that you could buy new for 360-ish, unless it had a bunch of upgrade stuff on it.

I don't know how many times I've heard "yeah it's only got 6 tanks through it". Not that it's not true in this case, but personally, if I buy any used nitro stuff at all, I do so with the assumption that the engine is toast and pay accordingly.

Just my 2¢