400+ whp with stock catback?
 

I am currently running an 02 dump with a full 3 inch turboback. My plan is to put the stock catback back on and run a boost activated cut out test pipe. Currently making 415whp, plan to make more power in the future.
Will I see the same amount of power as a full 3 inch exhaust with a cutout and stock catback, maybe more?

My guess is it depends on your turbo. If you're on small turbo,it should make more boost with cutout. If you're on big turbo, back pressure probably wasn't too bad of restriction, so you could see a tiny increase.

I ran that type of setup for a while (AMS downpipe to cutout in place of cat to stock catback). I didn't notice any loss of power from having the stock catback, but it was definitely nice and quiet on long highway trips. I'm on stock turbo so gains from that setup were probably marginal.
I've since changed my exhaust setup but still have the cutout and reducer pipe if you're interested.

Stock catback and a boost activated cut out work well. English Racing makes one using a 60mm wastegate.

Yea the English racing cutout is the one I was looking into getting.
Would you say the boost activated cutout is better than an electric cutout? What would the pros and cons be of both?

One is open whenever you're in boost (I think they put a 10psi spring in it). One is open when you flip the switch to open it.

You could also put a solenoid in line for the boost activated one so you can lip a switch and have it not open.

The boost activated cutout works mechanically versus electrically so it's more reliable based on the nature of the parts involved.