Hey mate, I have a 1999 R34 and im currently running the following
Im running a Kenwood KVT 532DVD (touch screen dvd player)
Kenwood dvd player
Pionner TS-A1702C in the front
Pionner splits
Pionner TS-D1602R for rear fills
Pioneer rear fills
So far it has cost around $1800 got the items on sale from auto barn. So im sure you have a hunt around ebay etc im sure you could find better prices , Not really fazed for a subwoofer just yet, But in the next few weeks will be looking into amps but yeah that falls in your price range