Has anyone replace the entire exhaust for a 2000 max? Does it really help increase the hp or acceleration? Is it worth getting? I was thinking of getting a cattman y pipe and catalyic converter and mid-pipe and etc...

 

Keep the stock cat. Its not worth getting an aftermarket 2.5" cat unless your stock cat is shot. There are no gains from it. The only part that you can't replace so far is the headers, unless you have them custom built.

Y-pipe increase= 13-15fwhp and shaves off about .2-.3 in the 1/4mile. Thats the biggest gain in the exhaust.

 

if you do replace the exhaust a test pipe is a good alternative to a high flow cat, couple more HP gain then a high flow cat and half the price, my buddies over at custom maxima sell a good test pipe and our exhaust just got finalized and will be ready for sale in 4 weeks.