in the knowledge that i get (it might be wrong, do correct me if other people know the real facts), rvr block are same with evos, bore,stroke, etc.... just maybe because of the piston dome different that rise the compression.....
for safety, both type of rvr if in stock form, better stay 1bar and below,even evo does this,the highest in stock is 1.2bar for e5-6, since i got ask mines japan last time regards my rechip ecu, they say if i boost more than 1 bar, the gasket probably will blown...
of course , if with proper add ons and tuning, even stock internal can withstand higher boost like 1.5 bar