after owning a few ra60's with 21rc's under the hood.. I can say that i was shocked and dumfounded that a crossflow 2 ltr could produce so NO POWER!?????!!??! well.. after looking at a few things i would bet my money on it.. that its the exhaust manifold that makes them go like shite.. If you take the covers off it.. Its one big tank, so all cylinders exhaust into one main point then it gets pushed throught the exhaust system.. I reckon a decent set of extractors would give you a little more horsies..