So i think the answer he was looking for was you can get anything as long as you get it engineered and then pasted the said emissions test and then the pits. But what i think he ment was whats the largest snail he can put in his engine and have it look stock, if thats correct i think somethign along the lines of a garrett 3076 can mount low i believe, but there are probably others and it all depends on what you are looking for horsepower wise etc. etc.