K03s. Word from the wise, dont waste your money on any K04, E05, or any kit that utilizes any sort of stock-like manifold/turbo set-up. If you want a bigger turbo and appropriate software down the road, Id suggest getting an aftermarket manifold with a T3 flange and a T3 flanged turbo (would be easier to recommend a turbo with powergoals and how much lag you can handle). If you're going to spend the money and time, dont waste it. As for software, unitronics has the most options (or atleast used to) for a "legitimate" big turbo system. But it couldnt hurt to see if Urotuning can accommodate your future BT plans.