Just thought I would update the thread on where I am at on my evolution of thinking on this upgrade project:
My CURRENT plan is to upgrade the OEM center and door speakers first and retain the head unit for processing and amplification for now. I got cold feet on deploying a JBL MS-8 after perusing some of the challenges others have had with this unit. (just seeing there were 8500+ posts in this thread scared the bejezzus out of me:
http://www.diymobileaudio.com/forum...udio-discussion/8257-jbls-ms-8-processor.html)
I am strongly leaning toward trying the least costly upgrades first, which means upgrading my front door and center dash speakers. These are things I feel comfortable tackling myself, and will add sound dampening to the doors too when replacing the front door speakers. (planning to use AlphaDamp since it is on half-price sale now at the DIYMA store)
I'm going to use the 3.5" Pioneer TS-A878 coaxial for the center replacement based on strong recommendation, and have a capacitor or two on hand for a high pass filter if needed (maybe try 100hz crossover point for a start)
I am still undecided on what to use in the front doors. The Hybrid Audio Technology Imagines (popular on the car stereo forums in the entry level of the high end lines) look like a fine choice, but wonder if enough sound quality improvement is going to be realized using the factory head unit processing and amplification to justify $300 speakers. It seems the consensus is that I should not just use a better 6 by 8 OEM size replacement but instead go to a round component mid-bass or coaxial. Lots of options here, but am considering just trying component speakers in the same A series as the 3.5" Pioneer TS-A878 or the next up D series for starters. I am not opposed to spending $300 for the HATs if worthwhile while still using the OEM processing and amplification at this point, but not yet convinced of the price/performance ratio in absence of upgraded processing/amplificaction.
Then see how much improvement I get from these low-cost steps and decide what to do next. Maybe I can get pretty good results from speaker upgrades and just add a sub for phase 2, eliminating the cost and complexity of an MS-8? If I do the speaker upgrades myself, even with getting a pro install for the JL Audio Stealthbox and amp, I will be pretty close to my $2K target budget. Adding a sub is almost surely in my upgrade path, and I am pretty smitten with the Stealthbox's "stealth" if not so much so with the price.
This is subject to change, but what I am thinking at this point.