What should I get next? Apexi WS cat-back or MEVI?

I have the following:
JWT Intake
Racing pipe
Y -pipe
VB Mod

I know that the Apexi only fits on 95/96 Maxima but I've read that it can be modified to fit a 99. What kinda of modification needs to be done for it to fit my max?

 

personally, a cat-back would be the last thing I would do, if at all. For a real performance mod to with the MEVI. I have intake, Y-pipe, MEVI and JWT/ECU and still have not gotten a cat-back.
Also, if you do the cat-back last you may actually be able to feel the gains.