Monoblock Suggestion?

Pretty tough question to answer Armandito !
Maybe listening to their stereos, or on to other thread postings.
I own and like monoblock amps too.
For *your speakers*, try looking up Dali MS5's through other discussion threads.
You can try to contact Dali over the phone or e-mail them for suggestions if you run out of help here.

Armandito, I have modified B&K M-200's, so they wouldn't fit your situation like mine.
Although it's time consuming and frustrating at times, try to contact a reputable dealer to find out what other MS5 owners are pairing up with, ya might get lucky, so hang in there.
Scour some of the A.A. threads.
B.T.W., my 91 RX7 is becoming an RX8 by me swapping in a V-8 engine.
Your Nissan twin turbo is a helluva sweet ride though !