I think you can't go wong on neither engines.
For peace of mind..
I did already 11.000 km with my B207L and Harrop, and that includes 2 trackdays and two 'training' day's on circuit.
No oil consumptions or problems with the engine.
With the 3.15 pulley on the Harrop and flowed head (exhaust side) and LSj cams I think I'm putting out at least 330bhp (dyno next month)
US guys do 400whp on the same engine but with turbo which gives more stress on the engine.
The REAL problem is not the pistons but the intake temperature..