A personal favourite of mine is a Sirio CL3B, with either its matching pipe, or a Hong Nor 2045 or 2062. In a buggy it's really smooth, but still has excellent acceleration and also has a blistering top end. In a truggy it's a bit underpowered low end so gets a bit hot.
http://www.benracing.co.uk/acatalog/...ng_Sirio_.html stock them, or
http://www.apexmodels.com/gbu0-prodshow/S21CL3B.html if you want to pay a bit more...
Hope this helped
Simon