Not 2 fucking bar that's for sure. I see about 13psi or so when up to operating temp at idle and the engine has been 100% reliable on track and thrashes for almost 7 years now. RST's don't have a lot of oil pressure at idle compared to most engines.

Standard HG will suffice, Airtec intercoolers seem to work very well fro the price and will be a huge improvement over the half width Pace which at best is very poor.