This is a pic of the JL Audio 450/4 amp that was in my C4S. Sounded great, but took up too much space. Plus you're always dinging it up when ever you load stuff in you trunk.

 

here's a bigger pic

 

damn that's a big amp! what style of music do you listen to? i'm guessing LOUD.

 

JL 330/4 here. They are the sh#t. There may be better amp maker, but these are pretty darn good. I have a good friend and fellow Porsche nut who had a competition stereo in a car, years ago... he swears by JL, and will use nothing else. Clean crisp sound. He paid for his equipment too... nothing for free. Won every contest.

 

I have A JL in my Toyota Tacoma under the driver seat. Wonder if there is enough room under a Porsche seat?

 

Not the greatest idea under the seat they build allot of heat and need room to breathe.

 

I like listening to Romo's girlfriends, Carrie and Jessica.

 

You cant go wrong with JL. Phoenix Gold used to be fantastic amps. As for the loudness. Well the trick is:
Alpine, Pioneer, Sony, have the tendency of telling you a wattage that is not even close to what they really put out. So I wouldnt necesarily believe what they claim.
With JL and Phoenix Gold, the output they claim is RMS the noise levels or almost inexistent. And because of the high power of these amps you shouldnt even turn the gains up. Also the crossovers that they use on their amps are of much better quality than the other manufacturers. Believe me, you will not be disapointed. As for the space they take, a good installer will find the proper mounting space with enough ventilation for the amp and with out killing your trunk.
GOOD LUCK!

 

A little electric fan (quiet) under the seat will do the trick.

 

can you give a link to an amp you suggest.

 

http://mobile.jlaudio.com/products_amps.php?amp_id=402
it seems phoenix gold has been bought out buy another company and im not sure of the quality of their products now.
Im sending you a PM with a contact who has done all my systems in the past.

 

my head unit does 50W x 4, but it overheats and breaks up.

1. how much power does the amp need to put out so that it doesn't break up?
2. is a 50W x 4 amp equivalent to my head unit power rating?

 

No, not really. When JL claims 50w per channel its really 50w RMS.
On an amp like this, you will only use the gains to better the imaging or staging of the sound in your cabin.
Unless you crank the the gains all the way up, the amp wont overheat.
What headunit are you using?

 

Your head unit rating is peak power--the RMS power (root mean square) is what you should be more interested in. for head units, RMS power is much lower (probably around 10-15 watts). That's why it breaks up at high volume. Picture a sine wave--when amps near the maximum power, the curves of the sine wave start to square off (think a curve with the top cut off). That's the distortion you're hearing.

Properly rated, high quality amps will give you RMS power ratings. As opposed to those crappy Boss amps that say 4000 x 4 watts.

That being said, JLs are very nice--I think they give constant power regardless of the impedance (which is nice). Audison is very good (but expensive). The A/D/S amps are great, but fairly large (at least the old ones were). I have Zapco amps--fantastic (but a bit pricey). MTX amps are OK--my old one tended to over heat though. Rockford Fosgate was once good--now I think they're a bit too mainstream and dumbed down. Arc Audio is nice (the head engineer used to be at Zapco). Brax/Helix are very good (expensive, and fairly large amps).

I think I'm rambling at this point. Anyway, for around $200 if think I'd go for a JL amp over Alpine.

p.s. gains don't effect imaging or staging--only volume. Gains should be set completely based on the input voltage of the head unit. i.e. turn the head unit almost to maximum volume...then gradually turn the gains on the amp up until you hear distortion. Back off a tiny bit, and the gain should remain there. The gain control is not a volume ****!
Imaging and staging are a function of speakers, speaker placement, your cabin and crossover settings. The gains may effect imaging/staging if you're bi-amping or tri-amping your set up, but most ppl just have their amps running components off a passive crossover.

 

my head unit is a Panasonic mp3/cd player. comparable to this one:
http://www.crutchfield.com/App/Produ...00&c=3&tp=5684
although ugly and non intuitive to use, it works fine-it's got the features i need. apparently no head units produce much more than 50w x 4, so i won't upgrade for power either.

is this amp a good hoice for my non-guru needs? i always thought Alpine was top-of-line stuff. guess not!
http://www.crutchfield.com/App/Produ...MRPF250&tp=115

or this sony, which is really small dimensionally
http://www.crutchfield.com/App/Produ...158XM4S&tp=115