At a crossroads, SB guys please chime in.

230lbs. sounds about right. W8 heads are not light weight pieces either. In building a 1000+ hp boosted engine saving weight in the engine is not the place I would be looking to save IMO. An R3 block and w8 heads are stout pieces and will live long and happy lives in a boosted application. Also a reminder that they are not cheap and easy builds for the timid or mechanically limited. They also came with many built in issues to overcome as rumble stated. Do some research and homework and make a educated informed decision and go for what your wallet and ability will afford. Good luck in whichever way your build takes you.