is your speedometer acurate?
if it is, you dont have 4.10s... unless you have a speed cal... the easiest way is to get a friend driving next to you at 80 MPH... if your speedo is 15 MPH off, you have 4.10s (you should be at around 3,100 RPMs)
they dont make a speedo gear (no matter what any one tells you) that will work with a T5/T45 to make your speedo 100% accurate for 4.10s... it would have something like, 28 splines, which is rediculous...
for a SN95 to have an accurate speedo with 3.73s and 4.10s you need a speed cal from americanmuscle.com... if you have 4.10s and a manual tranny, you'll shift into 2nd gear in the middle of an intersection, even if youre driving normally...
you'll finish the 1/4 mile at roughtly 4,000 RPMs in 4th gear
your speedo will say 90 MPH, your tach will say 3,000 RPM, and your car will be going 75 MPH...