I had a '78 model and used it to race desert. A lot needed to be done to the suspension in order to get it to work at higher speeds but mainly stiffer shock and fork springs. I had some re-valving work completed as well, and an increase in rear shock travel. BUT, the big thing was to change the swing arm. I had one of the first ProFab's for the IT175. What a BIG difference! Could not believe how much the stock swing arm flexed until getting this mod.
I also had quite a bit of porting done to the piston and barrel. It drank gas big time after that but it would haul ass. Super reliable and good bike even as a race only bike.