You want to at least hit the RMS rating of any sub if not push over it some. Too much amp power and your subs will suffer two ways. Either you will kick the cones and the VC's straight out of the basket, or, you will be turning the amp so far down that you will not have clean sound. The amp needs to work so that it can be as efficient as possible.

Underpowering can cause the same problems because now the amp will try to overcompensate for lack of power thus damaging the driver.

Make sure as well that you follow some good crossover points for your subs and get a good box.

A cap probably wouldn't hurt either. It helps with stable power. You have the battery charge the cap, amp gets constant 14.4 volts and is happy, car is happy cause it doesn't have to work so hard to keep up with the amp...and the A/C....and the highbeams...and the foglamps...and the underbody neon kit.....you get the picture.

Hope this helps
Rich


'96 Mystique, Zetec, MTX.
---Mods---
Removed both intake resonators and airbox. Installed APC air filter and APC crankcase ventilation filter. Removed exhaust resonator.
Installed XM Satellite Radio. Replaced bad alternator and 175a fusible link...much fun!
Intake plenum---GONE!!!!
My car growls louder than yours.
If I can't buy it, I'll build it...Trust Me!!!!