Now how in the hell do you answer this question? I started out with all OS and still have a EB Mods Speed, love that engine. I'm running a 5 yr old JP B8N with an onroad crank in my buggy, have had a blast with that old 8 port and it's a bad ass in truggy also. How bout the RB C6 USA modified by Murnan that i finally got figured out since it had a crack in the block. It hits in the mid range as good if not better than an OS.25 and walks away from it on top. Then i just got a Clockwork modded B5. It's got the bottom of a OS
.28 and the top, well more than it needs. Only engine i own that i have to drive totally different. Half throttle outta a corner is a handfull. And it gets the best fuel mileage. For $299.99 fully modded from Clockwork Racing Engines i will bet the ranch nothing in that price range comes close. I still have a blast with all 4 engines though. The right pipe, plug, head shimming and tune will make most any engine fun to race.