Yes smaller and alot more tracks run .21 for that class of buggy and if I'm not mistaken, R.O.A.R. runs the 1/8th buggy class with .21 engines. If I'm wrong please someone correct me. BUT, it depends on what .21 you get, if your planning on racing you need to get a .21 like the STS MKII it was designed by Rick Brake from R&B Mods and it was designed specifically for racing with buggies, his team cars are running it Or you can go with a novarossi or something like that, you would not be unhappy with either. Size isn't everything on the track anyway.