Cheap. I have direct ordering (great prices) and in all (including crap installed in the new thread I just made) ran around $800.
The MSRP on those speakers are just above $200, the amp is suggested at $425, and the subs at 120/per. About $525 got it all done. MSRP value of $875. A change in the way I have to order now has increased prices though, but not by much. Same setup to anyone now would be $600.
Labor will generally run about 30-40/per speaker pair, but im pretty cheap. Amp installations usually run about $80, but can run as high $150 depending on the installer and if a kit was used. Installation is not hard to do at all though, just a matter of popping on/popping off plastic and plugging the big prong onto the big tab and the little prong onto the little tab.
<span style='color:gray'><span style='font-family:Courier'>1995 e36 3 Series RIP
1999 e46 3 Series BURN IN HELL
2000 MR-S Roadster= Current</span></span>