There was an article recently on this.

I don't think anywhere in UK has come up with a guaranteed power output yet as they are still working on developing it.

Birds UK say they will probably do 2 conversions
One a remap for about 340bhp
The other replacing turbos ( originals are quite small ) etc to give maybe 380bhp.
I think DMS, CA Automotive, Ray West etc all said much the same - still under development.

Chipped UK ( Trubador?) reckon they can get about 360bhp-ish with a remap.