Do you have an exhaust manifold that fits the LET and Garrett T28?
If not, I know that Regal Autosport, UK, has (had?) a LET manifold that fits to a Garrett turbo, so.....
Motronic cannot see what turbo is on, only measures boost. With ph.3 you can run boost beyond factory settings, so it must be no problem, if your boostcontrol works good.....
Ask the creator of ph.3, Arno!
KKK16 is not that bad, but creates a lot of backpressure at high boost and high rpm's. Efficiency is also getting worse beyond 1,2-1,3 bar, so maybe a Garrett is indeed better here?????
(if your T28 compressormaps suit the LET.....)
Interresting project, keep us posted!
(contakt VMAX, I think they also run a different turbo on their LET)
Frank