My brother has an SI but i noticed the other day that it smoked and it has been going through coolant too quickly. it has decent performance but it has trouble starting up when its hot but not when its cold. it hasn overheated yet. the only thing is that whit smoke is emmited from the exhaust during shifting or mild acceleration. we are going to change the head gasket because thats waht i think is wrong. oil also looksa bit watered down even though it is 10w40 which i know is too thick but thats waht my brother uses. so what do you guys think it could be? and would changing the head gasket be too hard to do in the drive way? or could the motor be toast? it doesnt go thru oil but i havnt run a compression test on it yet. waht would you guys reccomend me and my brother do before we tear into it? would it be cheaper getting another used engine or rebuilding the one he has if it comes down to that? thanks and sorry if i was a little too vague.