Those who have been in the aero fray since gerhart first sold unit one will not get back into bed with another ..
In 1983 i had to make my own tooling to rebuidl the untis when the inevitable burn down took out the veins, then the old story of bearing float, race movment and just plain poor design cost not only thousands of dollars per season, but sent you back to the drawing board only to find the turbo and its poor assembly from aerodyne was the real issue.
Many auto customers sufferd dearly as the wick feed oiling of the undersized and underrated ball bearings just got too hot and turn soft.
YES, they do work within there design limits.
Yes , some very small changes have been made
NO they are not any different than they ever really were, maybe a little more passionatly assembled than aerodyne .
I have a soft spot for them, but not soft enough to justify the agg that goes with one in my end use of drag race or lake race.
ALL garrets have had liquid cooled centers for years..not new sorry.
Garrett , has much better flowing maps,
the 66 unit will make 400 hp at 25 + boost, but its over 120 degrees hotter air doing it than a typical 3071.
As it has been since gerharts dream first came to fuition,,, they are just another niche item, the niche never seems to dry up, just keeps replacing its lost follwers with new ..
Each has its followers,, like chevy, ford and bush..LOL
Use whichever makes YOU happy, the end result is they both provide more fun than a bottle of n20..
Gus