There isn't a necessary reason to keep the brand name consistent all the way across unless you are sponsored. Better to pick out the best of this, the best of that, and put it together that way.
I like your idea of PDX mated to JL sub(s). Had I not already had amps, this would be something I would be greatly considering.
I would consider whether you need one or two subs. I bought two 12" subs for first car, and it was a waste, whereas my buddy's cadillac fatty man car practically demanded more oomph. Since the sub is in the cab with you, I would imagine one would be plenty.
If you are still hedging between the ID's and the JL, the only person I know with experience here is Mr Marv
. If you are uncomfortable talking to him, I would consider talking to a formal car audio forum, such as http://www.the12volt.com/
, my two favorites.
For door speakers, I would be more inclined to the ID's over the JL's, as my prior research gives me the opinion that JL doesn't focus on door speakers.
To save money in this area, focus on buying the front speakers and leave the rear stock. More seasoned installers tell me that rear speakers are barely used, and are often much much cheaper. The installer will fade the sound almost completely forward, letting the front speakers provide realism and a sense that you have the singer standing before you.
This is my plan of attack - if I don't like it, all I have to do is buy significantly cheaper rear speakers at a later date.
We never got the word on what head unit you are thinking of... unless that's what you meant by NAV unit. In-dash NAV units are pretty popular with some of the guys here, and if you do go the double-din NAV route, try finding one where the screen can be removed and used as a GPS seperately.
Like you, I considered it a large expense and pieced things out with an Alpine iDA-X100 and a Garmin nuvi 205W.
(pic below, sorry if it's huge)
i am being an ass and forgot to say thank you for taking time to reply. so thank you.
I'm bored as hell at work today, so thanks for letting me rattle off! If I've been babbling, feel free to let me know!