Well... the thing about running lean. The prelude has no notion of "boost", and thus can't adjust its fuel maps according to boost pressure. You really need to upgrade the ECU and do a complete custom setup in order to get the fuel maps correct, and safely boost without risk of detonation. Also, did he give any examples of someone who has run 100k miles on that turbo?

The H22 swap is also a big pain, but at least it's a reliable N/A setup when it's done, and you probably have a newer motor with less miles. To do the swap, you need to replace the entire drivetrain, basically. Engine, tranny, motor mounts, axles, etc.

Mike