You need to post your power goals if want help with turbo selection.
I would suggest upgrading your fuel setup and switching to E85 if you have it available. You could probably run more boost on your current setup and get more power out of your setup.
I'm at 350 whp and 430 trq with a stock turbo and E85.
If you can't run E85 and just want a bigger turbo that still has good spool, I would look at the DOM 1.5 XTR. From what I saw, it spools pretty quickly and should have the flow to get you into the upper 300's on gas or break into the 400's on E85. This is the upgrade path I'm taking when I'm ready for more than what I've got now.