You're mostly right And you did nail the main difference of the 5th gen SH, which is ATTS. There's some other small things like you said...wheels, standard rear spoiler, etc. The base 5th gen is the "S" (not a Type-S).

Things got a little mixed up when you were talking about 3rd and 4th gens though. The 88-91 models were S, 2.0Si, and Si, and topped out at 140hp for the Si. Beginning with 92, the 4th gens were offered in S, Si, and Si 4WS, with the Si at 160hp. Add the VTEC model for 1993-96 with 190hp. 4WS was dropped midway though the 4th gen's run.

Hope that helped.

-phil
hp.com refugee