I'm pretty satisfied with the head unit I got from Bergvill FX. I have the Bose/MOST setup and the installation is clean and looks correct for my 2004 986.2S
This is what I bought and installed several months ago:
Head unit:
https://www.bergvillfx.com/index.php/products/car-audio/continental-tr7412ub-or.html
I had to email them for the "MOST/Bose" harness and it was about as expensive as the head unit but I didn't want to mess with rewiring everything.
I also had to buy an antenna adapter from Amazon because the one Bergvill had didn't work:
https://www.amazon.com/gp/product/B07WNN8RPZ/ref=ppx_od_dt_b_asin_title_s01?ie=UTF8&psc=1