using those figures, 5000RPM in a standard cossie T5 5th gear would be 130.08 MPH, and at 8000RPM would be 208.13

this is a good site to do gearing, final drive and wheel and tyre calculations
http://www.kabamus.com/garage/gears.html

and on 17" rims same tyre size 5000RPM= 135.72 MPH and 8000RPM= 217.14MPH