I seriously fought tooth and nail against going with a big name company for quite some time (first all one brand name system was Rockford Fosgate in my 2003 Ram, boy did I learn my lesson there...) so a few years passed and I found a great audio forum that really opened my eyes to the world of pristine sound reproduction. There are so many variables in an automobile environment, that you have to completely step back and tackle it from a different angle.
I used all home audio drivers for quite some time (Dayton audio midrange and midbass with Vifa tweeters running 3-way active on an Earthquake crossover and a DIYMA R12 subwoofer - all powered by Cadence TXA amplifiers) but finally ended up with Rainbow Germanium 6.5" components and a Focal 33A 13" subwoofer powered by Soundstream Tarantula amplifiers in my 2008 Ram. After trading it in on the 2010 R/T - I hit a wall at full force. That Alpine system is phenomenal for stock, but an absolute disaster for anyone wanting to simply upgrade the speakers. It has peaks and tweaks, and frequency cuts that almost make no sense at all. But it's what the manufacturer had to do to get the best out of the factory speakers.
The JL Audio CleanSweep with SSI Summing Interface takes 6 of the factory outputs (dash, front doors, and rear speakers), blends the signal together, flattens it out, and gives you four full range outputs to your amp(s). For someone wanting to absolutely crush the stock system (and most other setups) with excellent sound quality, this is definitely one way to do it.