I dont know if you have seen this, but TDI north are selling a stroker kit for the type-R engine. It can give an NA engine with over 300 bhp.
Have a look at www.system-r.co.uk or
http://www.todaracing.com/products/honda_k20a/stroker_kit.html
There seem to be a few different option for this, as well as some superchargers and a turbo kit.
The add in the mag I have list the stroker kit for �2560 + VAT.