ctrlaltdelboy - my retort 'dear boy'

I concede that the 'overall' aerodynamic drag of the NSX may be lower than the Cayman taking into account frontal area - I really ought to have taken this into account! I'd be interested in your data sources though - I couldn't find anything concrete through an admittedly brief google session.

There is no concrete data to prove the NSX power output is anything more than that stated by the manufacturer, so until proved otherwise I'll stay with 286bhp at most.

Weight has little bearing on top speed, a 120bhp/750kg Elise tops around 124mph, and a 113bhp/1125kg MINI Cooper tops around 125mph (source Autocar). Nonetheless, Autocar quote NSX 3.2 @ 1320kg & Cayman S @ 1340kg - insignificant.

There is no supporting evidence which states the Caymans power curve drops off after peak power at 7200rpm; chances are (and this is surely borne out factually by the Caymans S top speed) the power output stays more or less level from then through to cutout.

I do believe the Cayman develops more bhp than an NSX, this conclusion is drawn both from on paper stats (and my interpretation thereof) and actually driving the 2 cars back to back.

So:

1. The Cayman has more power (proven, on paper, factually quoted)
2. Almost exactly the same weight (which has little effect on top speed anyway)
3. Alleged marginally more drag, although sources unquoted

So @ 171mph - speed is higher just as I would expect.

If someone can prove their factory spec NSX is capable of 180mph or more in normal circumstances then I'll happily eat a Honda hat. Otherwise, claims of realistic 175mph+ capability remain poppycock IMHO.

For the purpose of adding balance - people never cease to be impressed my my NSX's acceleration and speed capabilities when they experience it; I am certainly not underestimating NSX performance rather just trying to add a degree of realism to the discussion.