The GM8 turbocharger isn't as bad as everyone "thinks" it is. The numbers I pulled in my signature line were with a GM8.

Now, are there better units out there?

Heck yeah, the GM8 has design roots as far back as the early 90's. There's been lots of advancements since then.

Would I be using a Chinese knock off turbo or a Holset take off unit to replace it?

Nope....I'd buy a new one after some serious consultation with a manufacturer. Big bucks though, better get ready to pony up new unit prices plus a premium for going where no one has gone before.

I really like the BW EFR series. Not cheap by a good margin though....