Underdrive pulley gimmick!

[mysweetlx]

I searched the archived threads and couldn't really find an answer to my secific question. I've got March U/D pulleys and my battery is constantly dead when the car isn't started for 3+ days......the lights dimming at idle (@ night) is also a pain in the arse. I'm planning on getting a Optima red battery soon......and thinking about putting the stock pulleys back in.

Do you think I'll be OK w/ just the Optima w/ the UD pulleys, or do I REALLY need to step up to a 130-140 amp alternator if I keep them in (I'm not into stereos either). I'm thinking that losing possibly 5hp might not be as bad as spending the $200 on a new alternator.

I've only read about the 5+hp gains in the mags......and I've honestly never witnessed that gain in person at the dyno. I have seen a 2rwhp gain on a moderately modified stang (heads, intake, cam, etc etc), but that's not really noticeable at all.

Any thoughts?