Fun fact - the stock 4G54 bottom end will run 600 HP. The thing that strangles these engines is the cylinder heads, HKS made twin cam heads for the 4G54 and in NA form produced 276 HP as part of a full performance package (headers and twin Mikuni PHH carbs) They are rare as hell now. A freind and myself debated over whether or not an E30 twin cam head could be modded for the 2.6 block but it would take some assing to get the timing cover and chains to work...