Which gives better sound upgrade? Replace BOSE amp, or replace CDR-24?

Forget about non-audio features. I don't care much about Bluetooth, phone connectivity. I don't have and would never use NAV. My 05BS is not a daily driver. All I want is better sound. I currently have BOSE with a Dension Gateway 500 using an iPod as source. If I had to choose between the two, would I be better off replacing the BOSE amp , or replacing the CDR-24 with a head unit that can directly play digital music files?

I'd have to ohm out the speakers at home but most likely if you replace the Bose amp you have to replace all of the speakers at the same time. Bose typically will use really funky ohm rated speakers in their systems which don't play very well with aftermarket amps, typical car speakers are 4 ohm and Bose likes to use 1.5 and 0.5 ohm speakers sometimes. Replacing the headunit would give you a degree of ability to alter to sound, and I don't know what your opinion of the current system is, but to really get better audio quality it's hard to beat replacing the amp and speakers.

This is what I decided. I didn't want to have to do all of the speakers, likely all of the wiring, etc. I am keeping the Bose amp and speakers, using a MOST interface and third party head unit with EQ to compensate and tune.

Because you have the Bose system - it means odd impedance's at all of the speakers, an interesting crossover system, as well as a fiber optic input to the amp... Before you toss your credit card down make sure all of the speakers are working. It's not uncommon for a factory speaker element to tear away from the frame. Then decide what you want to do. Replacing the amp and speakers will give you more sound. Replacing the head unit can give you more options - like bluetooth phone and music... I replaced the head unit and used a NAV converter to feed the signal to the existing amp and speakers. The sound quality dramatically improved. The CDR-24 was muddy, the kenwood I put in woke it right up. And, added navigation, carplay , hands free phone, etc. It also got rid of the user hostile CDR-24 - mine had a delay after every action, push a button, delay, turn a knob, delay... No matter what you do - accept early that it's going to run roughly $1000... I looked at every solution, and wrapped myself around the axle multiple times. No matter what option, it was a grand... I also learned years ago - any money you put into a car stereo you will never get back. Decide how much you you want to improve the sound, and add to your enjoyment in the car, and how much money you can walk away from when you sell the car...

How much did an EQ help with the sound? How many speakers are in the Bose system (I have a Boxster so no footwell sub) and are all of them still active after a head unit sap with a MOST adapter? Sorry for the tardy response - I'm not getting Planet-9 e-mail notifications all of a sudden.

Thanks for all that info. I'm unlikely to sell the car - I put less than 3k annually on it as a fair-weather driver. $1k would be about the max I'd want to spend anyway because of the annual mileage. CarPlay would be nice but I would likely only use Music and Podcast features. I'm mostly interested in sound quality, not features.

Hi there I am thinking of doing the same. Do you have the link of the most interface and with third party head unit did you go for? Are you happy with it?

I haven't installed mine yet, as all of my weekends are taken with other projects. So, i have an impressive stack of boxes for the project. I started with Jim Roal's thread and blog about using the Pumpkin PX5-based Android head unit. More info can also be found here, for the technically minded. I didn't want to spend over a thousand dollars, and I sort of like hacking cheap Android devices to do more, carputers, etc, so it was interesting to me. I bought the Longate MOST adapter, running $99 these days. I used the CAI installation kit with harness, $85. Changed out the backup camera for a small wedge-shaped one off Amazon. Bought some noise isolators from Amazon, at Jim's suggestion. Note sure when i will be able to install, however. I still need to run the backup camera line through the driver's door sill, and then look at the HU install. i'm not even at $500, yet, however.

Sorry if this is off-topic but what is your issue with the Dension 500? I'm looking at doing the same to my Cayman and just use Aux for stereo input. Is it noticeably different than CD quality? The radio sounded bad to me but stereo through the Bose sound system and cd changer always sounded good enough for my ears.

I recently upgraded my 987.2 CDR-30 SPP headunit to an aftermarker headunit (JVC KW-M845BW). Because on my SPP system the headunit doesn't directly drive any of the speakers (same story with BOSE I believe), I didn't notice any sound quality improvements from the speakers. I was able to adjust the equilizer to help a bit, but since my headunit doesn't have a DSP w/mic calibration I wasn't able to do too much. Biggest gain for me is my factory CDR-30 had a problem with the AUX input gain, I could never get enough volume on the AUX input (and I'd blast my ears if I switched to AM/FM without first adjusting the volume). The headunit thankfully fixed that problem. My next step is to install an amp with highpass (mids/tweets) and lowpass (woofer) crossovers to replace my existing ASK amp as well as some 4" midrange speakers. Not sure what I'd do with the BOSE setup since you would probably need replace all speakers and your amp (possibly wiring as well) at the same time.