Did you install an aftermarket amp or did you wire the speakers directly from the HU?

Best,
Brad

I wired rears to the head unit directly, and the rest went to the existing amp. Got new front speakers coming. May replace the door subs with 2-ways. Will decide after I hear how the new fronts sound.

Replaced the front speakers with Alpine. New speakers are not slam dunk better.
 

Replaced the front speakers with Alpine. New speakers are not slam dunk better.

Short story. No better at regular listening levels...perhaps even a little less high definition vs. stock Nokia speakers (with separate tweeters.) Maybe a little better high power handling, less distortion at high listening levels.

Long story.

Earlier I added a hard rear shelf and Pioneer speaker kit. Huge improvement but the fronts sounded crazy bad...all treble. Strangely they sounded worse than before the rears were installed but I figured it was the comparison that was the cause. Saw a used set of front speaker assemblies with Alpine SPS-410's already installed and bought them off Ebay for the same price as the Alpines alone sell for. I've seen a few threads where these Alpines were recommended.

While waiting for that order to arrive had to remove the head unit to install the backup camera and found one of the speaker wires stripped. Fixed it and low and behold front speakers sounded much better! Still not as good as the rears, but much fuller sound.

The new/old Alpine SPS-410's arrived. Decided to install one to do a side by side. The difference was almost imperceptible at lower volumes with a little more clarity going to the original Nokia speaker because of it's crisper highs. When cranked really loud the Alpines distorted a bit less...were less muddy.

Overall, not really worth the money or effort. I'll probably keep the new Alpines in there just because I'll have better luck reselling the stock speakers on Ebay.

I'm wondering if I should just stop there or look for better performing dash speakers. I read good things about Infinitys. Alternatively I was thinking of replacing door subs with 6x9 two ways.

Advice?

Replaced front speakers with Infinity Reference 4002CFX, HUGE IMPROVEMENT!
 

Replace Alpines with Infinity Reference 4002CFX. The Infinities are slightly lower rated for power (35 watt continuous vs. 45 for the Alpines) but have a much better sensitivity of 92db vs. the Alpine's 86db. That 6db difference equates to 4 times the volume at the same input power level. This means the amp doesn't have to be driven so hard to produce the sound.

The improvement in midrange is considerable. This really helps "fill out" the sound, from the rear speakers. Even at the highest volume level the Alpines could not produce the same amount of low/midrange as the Infinities do at half volume. The Infinities are rated at 75-21kHz. The Alpines at 97-22kHz.

One note, the Infinities are a slightly deeper speaker and magnet bottomed out on the passenger side (1 7/8" vs. 1 11/16".) It doesn't seem to cause any issues with output or vibration noise. If I were to do it again I'd look for a shallower 4" speaker with the similar efficiency and performance.

Discovered another "surprise and delight" with the Pioneer 6200. When listening to a CD a little red symbol would sometimes appear at the lower corner of the screen. It was the road speed limit and it would flash on any time I exceeded the speed limit. Nice touch.

Thinking of getting this head unit for my 03 with MOST system. I know I'd have to replace or bypass the amp also. I'm also going to install the rear speakers. I currently have the HiFi option, so dash speakers, door subs and an amp. So a couple questions for anyone that can help.

How do the door subs currently get powered? Off of the existing amp through separate channels?

And if I put in the new HU (and possibly new amp), how do I power the dash speakers and door subs?4 channel amp? 6 channel amp? How is the crossover done for the subs?