the technology that Eaton used when they designed the M90 was from the mid 90's, and turbo technology has come so far since then. with compressor maps all the different nozzle's available you have so many options that can dramatically reduce spool time while still making decent power. I saw a guy who twin turboed a 3800 engine in a sand rail with 30mm turbos, and that thing only made 300 hp, but it made that power at like 2000 rpms.