Originally Posted by Mike Rainbird

As a rough guestimate (going by a fixed* tyre circumference of 1947mm for a 235/40x17):
7800rpm = 194.45mph on 0.80 fifth gear and 3.64 final drive.
7700rpm = 191.96
7600rpm = 189.46
7500rpm = 186.97
7400rpm = 184.48
7300rpm = 181.98
7200rpm = 179.49
7100rpm = 177.00
7000rpm = 174.51

*due to centrifugal force, the diameter actually grows slightly, so you may achieve fractionally higher speeds than quoted, or as Nick points out, the above circumference is based on a new tyre and an almost fully worn item could be up to 1.5% less speed.