Radio Replacement keeping OEM Bose
 

Look at this on eBay:

https://www.ebay.com/ulk/itm/272118203813

Radio Replacement Interface & Steering Retain SWC for Nissan/Infinity w/OEM Bose

Has anyone installed that part and kept your factory Bose speakers but added and aftermarket head unit? I'm wondering how well the Bose speakers actually sound after. Any input would be appreciated.

Ditch the whole Blose system. Only ~ 100 threads recommending the same thing.

Like they do now... pretty crappy. The head unit will not matter as its just sending data (sound) to the speakers. You can't "hear" the head unit, you can only hear the output from the speakers.

To me only legit and logical reason to change head units is to gain features like Bluetooth, iPod, Navigation, SiriusXM, etc. Only the more expensive head units that contain special parts (amps) or processors (EQs, DSP, crossovers, etc) will create an improve in sound. And in most cases it takes even bigger amps and better speakers to hear those small improvements.

The BOSE is a system -and a terrible one at that- it was only designed to work with all of its original parts. When you replace one part you now have a single out of spec part added into an already weak chain.

Of course you can "hear" the head unit. For example, when I was replacing my non-Bose system I installed the new Kenwood HU first, and just for curiosity, before I installed the new amps/sub/speakers I listened to it withe the OEM speakers. I was surprised that the system sounder much better than it ever had. If you don't have a clean output from the HU, nothing downstream will improve the sound of the system. Get the best HU you can afford and if that's all you can get now, install your upgrades as you can afford them later.

That said, all the Blose parts are crap, and really not compatible with aftermarket pieces, so as mentioned, it's best to junk it all and start over. Changing the HU and retaining the Blose amp/sub/speakers will only yield you more features now, and there's little chance the system will sound much better. I don't know, but that may be all you're looking for. If so, have at it.

I used an older version of that PAC adapter to use with my aftermarket head unit and Bose speakers/amp. Like everyone has already said, it will sound exactly the same just with a new head unit. But I'm not an audiophile and I wanted to stream songs via Bluetooth so it was fine for my needs.

Well with the non-BOSE system the head unit is really a source + amp, so replacing it will improve the sound because the aftermarket head unit's amp is better then the OEM one. However with the BOSE system swapping head units gains pretty much nothing sound wise since the crappy amp and speakers remain.