Consider a set of UMW ZC turbos too, I've been very happy with them and Kevin's support, advice and tuning are the best I've experienced in aftermarket mod world.
Zero issues in first year/7k+ miles.
Supporting fuel system, injectors, FPR, additional pump, and redundant wiring/relays with a mind towards preventing disaster made are all important considerations depending on what you desire.
I went down from my stock X50 K24's to his K16's and the car drives like there's a big block V-8 in it now. The ability to keep up with or ahead of new Z06 vettes on the track is night and day from how the car was prior to his kit.

 

I had the zero clearance back in 2003, you should have told him to upgrade your k24s instead... I think you made a mistake and left HP on the table...
but thats my opinion since I did go from k16s to k24s to his k16 ZC back when turbo options were very limited..... the k24s have better flow up on top...

 

I figured the K16's would be better suited to my track use.
Powdrhound's experience with the same ones was enough for me.

Some day I'd love to do studs, rods, port heads, etc...and run a 1000hp one but I'm having fun with my set up on track for now.
Still have a virtually new set of k24's in case I get the itch too

 

Oh ok. Track guy. I understand

 

Kevin won't do K24s anymore. Did it a long time ago but no more...

I have his K16 on a built 3.8 with RSR crank, pump, heads, etc. No complaints.... Pulls to 7500+ without let up... HP peak is actually at 7200..

 

I had no clue he doesn't make them. But I don't track like you guys do so k24s are a lot more appealing to me due to the hot side for too ends.