I'm curious of the same thing with my etec 90. The top RPM on it is 5600 and my normal cruising range is 4600-5000. My mechanic says it's made to run at that high speed, but I'm a little uncomfortable running it that hard.
2015 Seaark 1872 MV CC Etec-90
Two Helix 12 CHIRP SI's, , MinnKota Riptide ST80/i-pilot Link, Bob's Hydraulic
Bitter Gun Owner