I do know now, I have fuelling on full boost on fifth gear up to 6000rpm (ca 1.3bar) (where we stopped, foolishly. Will have to do a full rpm session again on fifth gear).

The misfires were down to 0.9mm gap on the Iridium plugs. With 0.7mm gap all was good again!

I'm a happy chap with a great Coupe. On fourth gear the load on the rollers was low so I only got 1.14bar/275.2whp at most.
Will do another round (in 5th) when the snow melts next spring.

Here's one graph from the latest RR-session (with misfire; seen as the small dip).

If anybody's interested in my process of changing to a GT28R there's a long project thread with lots of pic's HERE.

Anyway, it seems this project is finished now.

The car is MUCH more drivable than before with great off-boost behaviour and some ferocious thrust up the revs, especially at 5000rpm where the 1.45bar kicks in..
On top of that, it's more frugal than before.

I'm very happy with Flea's service and will recommend him to anybody here in Sweden too.

good work Per & flea,,, he did it with me before and here you go

keep up the good work and enjoy the car to the max

Great work Per, I enjoyed 'looking at the pictures in your Swedish thread, just how I read my books that! ......

Per, what are those wheels you have on your car, I think they look great?

Phil

Don't they? Thanks!
They are Liquidmetal Static 18x7.5" with pcd 4x100mm and ET45. So with 8mm hubcentric spacers and wobbly bolts they fit perfectly.
I bought them (CHEAP!) at discounttiredirect.com

I'd like to add; the biggest (and for me, the only) downside of having the ECU boostcontrol: The difficulty to get the correct reading on RR-sessions (less load - lot less boost).
As mentioned earlier, I got 275whp at 1.14bar (max 1.31bar)
What I get on road, with 1.3bar (max 1.45bar), I have no idea.
Yet.