Is it worth it to replace the rear? I've done everything else except the rear but not surre if it would be worth the $ to change it out.

 

It's a no brainer change it!!!!
Most people want to build their quad faster by starting with the motor but if you don't have the right suspention, the motor won't matter. "smoother is faster".[img]i/expressions/face-icon-small-wink.gif[/img]