RE: AVOID THIS ENGINE AT ALL COST!!!!!
Since everyone has mentioned their favourite .46's, I'll have to mention the engine in my trainer at the moment; the Irvine .46. Great engine, far more powerful than the OS.40 FA, though marginally less powerful than OS.46 FX, but far cheaper than both.
Cracking engine, very reliable, good for any trainer ,or any low winger for that matter