RE: Looking at custom building one
there is one thing you need to watch for with MIG welding though, cold over-roll, you can have a perfect looking weld with no penetration, you gotta either use a flick motion or a circular motion to keep the weld pool on the parent metal and not building on top of itself, certainly though if you know how to TIG weld that is the best way to go, very strong, very clean, and you can listen to the radio while you weld lol (my favorite part about it).
i love the idea of the 1/5 scale drag car, i'v thought about it but i cant get any good engines around here for a good price, mugdy (spelling?) got the idea rolling for me, but i think i mgiht stick with my revo until i can find some 1.5% chrome-molly tubing and a decent engine for a reasonable price.