i would go with the us w/ the euuro trans. it will be alot easier to wire up. also the cost of the euro engine compared to the money you can use to mod the us engine. i had the m50 installed in my m so if you need any help with a parts list let me know i wanna do a e36 swap but what would it cost me to get the euro engine and 6 speed tranny cus i want that over 300 n/a hp in my e30 or would it be better just to do a e36 u.s with a euro tranny