alternator pathfinder

Right now in an '05 Pathfinder I'm running a 1.600 PDX amp with an older 200W Alpine 4ch that I'm looking into replacing with a 4.100 PDX amp. Right now when I turn my system way up it'll dim the lights pretty bad and I'm afraid that if I put the more powerful pdx in that it'll make my problem worse. Right now I've got the big 3 done so I'd want to put in a ho alt since my factory alt only puts out 130A. If I have both PDX amps in I should be up to 140A just for the two amps and on top of that run my car so I figured maybe a 250A or 300A ho alt should be good right? The other problem is that my pathfinder is a nightmare to work with under the hood (let's cram as much crap in as small a space as possible!) so does anyone know about how much an install on an '05 Pathfinder might run before I go and spend a lot on a shiny new PDX?

Using that much power is not good for your alternator, but before you go and changing that out, try using a capacitor or two or even an extra battery in your trunk.  I ran a 1600 Watt fosgate amp, and two 400 watt audiobahn amps that dimmed the lights so bad i wouldn't turn up the stereo, and i had a 1 farad cap too.  I added a deep cycle in the trunk and it worked perfectly.  Not to mention i left my headlights on one day for 12 hours and my car still started.