They were not cramped and slow in comparison with the standard Shadow which was most of them. Can't recall any review putting Shadow above either one. Can't recall complaints of them being cramped, either. Usually you have a bunch of specs. In this case the appropriate spec would be front + rear legroom (given that even then, seats moved).
The base Civic was slow, the midline Civic was a match for the heavy Shadow, the Civic EX was well over the Shadow in acceleration, as I recall from the day.
Consumers Guide on the 1988-89 Civic - this is before the 1990s 1.8s, hp was pretty low (70-105). 1.5 or 1.6 engine. By the time I was looking, they were up to 80/100/125 or so. However, weight was just 2,000 lb (4-door). Consumers Guide reports, “Interiors are roomy...
performance is brisk with manual shift, since the engine revs up nicely, but sluggish with automatic.”
Corolla, 1988-89: 90 or 115 hp. Carburetors!! Ouch. Oops, 100 hp fuel injection for 1989. “If you like high-revving engines, you’ll love Corolla’s, which is also smooth and responsive. The precise 5-speed makes driving even more fun. ... ” No real comments on interior space other than “rear leg room so-so (worse in the coupe).” Weight: 2,406 lb.
Shadow: pretty complimentary compared with Consumer Reports' hit pieces. “Both 2.2-liter engines are noisy, but the turbo delivers 146 horsepower for snappy performance.” “Back seat is tight for grown-ups” - base engine 93-97 hp, 2.5 liter 95-100 hp, then turbo 146 or 150. Weight, 2558 lb for the four-door. So a little more horsepower, (a lot more torque), and a lot more weight.
I don't see the needed interior dimensions here so it's subjective. They were all called subcompacts.
Yes, the turbo four was great. But they designed the engine bay to hold too large an engine, so the Sundance ended up 150-500 lb heavier than its competitors.