'87 3.2 with SW (93 octane) chip, fabspeed Euro premuffler, Dansk 1-in-2-out, and Euro ride height.
OEM 16 inch tire sizes (205-55-16, 225/50-16) and OEM F & R spoilers.
I don't know the real speed, but I do know my speedo is 2.5% to 3% optimistic and the indicated was just above 145, and I wasn't quite at redline.
Man, the car is LOUD at that speed, between wind noise & exhaust noise (and the loud pounding of my heart). And the last 15 mph took what seemed like a LONG time.
Car & Driver claimed a top speed of 149 in their review of the 3.2 in February 1984, but they also claimed that car did a 5.3 second 0-60 and 13.9 sec/100 mph 1/4 mile.
C/D also had the top speed of an SC at 130 (8/80 issue).
Bottom line: If you are only seeing 135 with a 3.2 something is wrong. That sounds like SC top speed.
But, as was previously and very correctly stated, you need a lot of time & distance to really get close to top speed.
When I first got my car, it still had the original catalytic converter, and the throttle linkage was not allowing full range of motion. When I took off the cat and shook it, it sounded like a very large maraca, so it was probably seriously clogged. Fixing these made a big difference, but of course the mods listed above did too.