K20A2 head with K24A4 block might be more expensive than getting a complete engine.

But I saw a complete K20A2 head on eBay go for about $850 a couple of weeks ago. TSX block may be a little rarer, but my understanding is you can use an Accord K24 block if you do some work to it first.

A properly tuned BASIC N/A setup (this means I/H/E/IMG/KPro, maybe K2 cams if you're feeling rich) would net you about 220whp and around 180tq. That's very impressive torque.

Some also say that since the TSX block doesn't rev high enough it would be in your interest to destroke it to 2.2L to create a "K22" for high revvability with excellent torque