youll need the Kooks midpipe, the Kooks arent a true long tube (not knocking them all btw) when compared to other long tubes on the market, they are shorter and therefore there is no way to substitute the midpipe
Not to the best of my knowledge. A friend of mine up here ran the Kooks 1 7/8 set up on his car with their off-road X last season and he didn't have any fitment issues.