I don't think you will get a chance to test your speed limiter at Lime Rock...the main straight is not that long...the funest corner is the downhill...you shift up under the bridge as you dive down the hill and get full throttle at turn in and pray you don't early apex it.
The most difficult for me is turn 3 the left hander.
If you want to do a cyber test of the track...pick up a copy of EA's Sports Car GT...and take whirl in a Porsche or M3.

Yeah it would be great to have A 500E an E55 and CLK55 on track...wouldn't it?