im not 100% sure on the scale but its just as big as a stock body slash just with some small overhangs. its not too big.
as for racing, OY, where do i start. body parachutes like crazy! had to ream holes in the rear window to keep it level on the 2 doubles we have here. body roll is enormous and you need stiffer springs and oil to compensate. roll over protection is much higher as i took a few barrel rolls this evening with no issues except for a small tear at the front bumper level.
if you do want to run the body i suggest reaming 5-10 holes in the rear window to reduce the parachute effect. i switched from 35 weight oil to 40 weight all around on losi "green" 2.5" springs with the large traxxas preload front and rear. as for the body, i used stock mounts front and rear with the front of the body cut out and sitting above the tires, for the rear i set it as high as possible with 2 bolts per side and it works good enough to set at the correct height.
i will competing in the sportsman class on Wed and i will let everyone know how i do with the SCT(short course taxi) against the random mix of other cars/buggies/trucks. its an open novice class with the only restriction being battery size of 7.4V LiPo or 8.4V NiMh. motor and chassis is unrestricted.