Anybody tried as an alternative to stock?

 

GTX2867R you mean? At 47 pounds/min, it would be more similar to the FP White or HTA68. The stock IX turbo simply doesn't have the compressor flow to keep up, although at sea level type elevation, it's not nearly as much of an issue as the turbine wheel runs out of steam not long after the stock compressor wheel. At elevation though, it's a considerably different story.

I was looking at it a lot a while back and I'd still like to pick one up for another application. To me though, it came down to the turbine wheel for the performance difference and then packaging/weight.

GTX28XXR / TD05HR Turbine dimensions

Major Dia: 53.9mm / 56.0mm
Minor Dia: 47.0mm / 49.0mm
Blade Count: 9 / 12

The GT28 turbine wheel is a very good wheel that flows extremely well for it's size. The GTX match wheels are also showing very high overall efficiency ratings on the product info sheets. The TD05HR on the other hand is also a very good wheel and the extra size should help make up for the higher flowing GT wheel. It is also in a twinscroll housing which is a good thing, IMO and will make up for the added inertia of the higher blade count and larger size. The TD05HR may be more efficient overall. but it's just a guess.

I'd honestly call it a wash on performance from a numbers perspective.

The only benefit the GTX has is weight, if you are into that sort of thing. The GTX28 turbo in a tial housing should weigh around 10 pounds. Add on 2.5 pounds for an MV-S gate and you are under 13 pounds for the turbo and wastegate assembly. The IX turbo is right around 21 pounds with the wastegate actuator.

The question becomes, is V-band fittings and 9 pounds worth the added cost for a custom setup?

At least, that was the conclusion I came to...and yes, it is, although I went up to the GTX3071R in the Tial housing with the MV-S as I want 500WHP.