torque spring

[JustRigIt]

I have been looking into finding a cheap ways to improve my gas club car. I found out that you can add a torque spring (power spring) priced around 50 bucks and discription says it adds 200rpm. I thought 50 was high for 200rpm and kept looking untill I found a few torque spring for 19 bucks.These springs are not designed for a golf cart but their discriptions say 1000rpm, 1500rpm, 2000rpm and 2500rpm. They are also the same size as the one for the golf cart.
I've done some testing on my cart and acording to the tach the rpm limiter cuts out at 2000rpm. I was reving up the engine and I got around 3000rpm and then a funny noise started so I put my red line at 3000. What would be the best torque spring to put on it? What would be the difference between the 1000rpm and the 2500rpm spring be?
Thanks in advance, I know the basics but learn something new everyday!