The thought had crossed my mind as well but i didn't for a couple reasons.
-Even with cams i think you'd need headwork to fully realize the gains
-I was skeptical about opening the motor up...there is alot to be said about OEM reliability and build quality imo.
As far as i saw it, the costs to do what i'd like to do right, made it not worthwhile anymore. If the motor was blown or had some spare heads to work on i'd have given it more consideration. The main downside to me was that for anything that wasn't a dedicated track car it wasn't worth it to me. Doesn't mean it won't be to you, just some food for thought.
IMO if you're going to build a motor, build it as a race motor all the way and treat it as such. Although i'm a proponent of adding forged pistons to an ej257 whilst leaving the rest of the longblock untouched.
Hope this helps.