Calculating using our drag coefficient and frontal area, and assuming a 25% drivetrain loss to the wheels, you'll run out of headroom in an L36 somewhere between 135 and 140mph. This is assuming a bone-stock L36 in decent condition, running well, with no power-adders.
Same thing for an L27 would be 125-130mph.
Same thing for a 92/93 L67 in theory would be the same 135-140, but the factory-underrated spec may surprise you.
Same thing for 94/95 L67 would be 140-145mph, but again, L67'* are traditionally underrated.
Same thing for a 96-99 L67 would be 145-150mph, but is also underrated.
All these calculations are done with the 92-99 Frontal Area and Drag Coefficient. I don't have the data for the 87-91 body style, nor the 2000+. All these examples are assuming the factory hp spec is correct, and your bone-stock car is in good running condition with a 25% drivetrain loss, and you have removed the top speed limiter.
Calculating hp loss with Aero drag is an interesting subject, and is purely mathematical. These numbers would be very close to reality. Just remember that Aero drag is a cube function. The faster you go, the worse it gets REALLY quick. Adding 5hp to any car here wouldn't add much top speed before you hit the wall.
Now let'* make it a little more difficult, shall we?
You MUST be at your peak RPM for horsepower in the proper gear in order to make this work. If you are 2000 rpm'* above your peak of 205hp in an L36, your 'real' horsepower at that moment is significantly less, and you won't be able to achieve that top speed. You must select your gear carefully. Calculating gear ratios at a particular peak rpm would be another case study.