you will need to put all the EGR(polution gear) stuff on it if your going to engineer it as L20b didnt come out in a pre polution vehicle. Then the question is will it run with all that if its heavily worked ? Anyway could all be irrelevant as you may have done all the research. L18 and L16 are easier there a shorter block (height) and give you more bonnet clearance especially with a 200b or bluebird sump and oil pickup. Trust me im doin one and have L16 in the car waiting for a sump etc to get it lower and make mounts.