Us old guys know how under powered those cars were so if you had one that had some power it would be a sleeper to us.I'd definitely prefer a sleeper, but it looks like no GM sleeper candidates came with a manual trans.
The third gen Camaro looks pretty cool. I don't know much of anything about them. I like the look of this one but it's outside my price range: https://denver.craigslist.org/cto/d/1991-camaro-rs/6736987267.html
When I think of sleeper, I think of dropping an LS3 with 6spd manual into something like this:
View attachment 283876

BMW?98-03 BMW 540i. 282 hp V8, 6 speed manual trans.
Not much decent GM stuff between '75 and '08 fitting your wants IMO.
98-03 BMW 540i. 282 hp V8, 6 speed manual trans.
Not much decent GM stuff between '75 and '08 fitting your wants IMO.
I think they look way better with a little bit of lift and tire. A buddy of mine had one in the 90's that I really liked.I'm not a huge fan of the front-end for this generation of S-10 but check out the condition of this truck. Would last me a lifetime and I'd be 100% GM.
https://denver.craigslist.org/cto/d/wd-43-v6-5-speed-low-miles/6746038483.html
I'll echo the Cavalier statement. The 91-94 Z24s came with a 3.1l V6 and you could get the manual transmission. It's no Vette killer but they'll book. They also came with quite a bit of chassis bracing the standard Cavaliers didn't get and with some new shocks/struts they'll handle really good and are fun to drive.
If a manual isn't entirely required, look for one of the supercharged 3.8l Bonneville or Grand Prix sedans. I'd wager they'll hold their own against one of the Impala SS cars.
Denver is really delivering on low-mileage GM from '85-'95 this week:
https://denver.craigslist.org/cto/d/1994-chevrolet-cavalier-z24/6743612991.html