If I were you, I would stick with one good set of components, an amp and a good HU.
Alpine and Eclipse are both good for HU's. If you found one for less then 350 I'd be suprised.
Nak is very good, unfortunately they have load mechanism problems. Even giving this, I would STILL own on. The price is very reasonable, and before Denon entered the HU market, Nak's were the standard by which others were measured, running with top end Alpine's and Eclipses.
Anyways, amps are amps. As long as its a decent name, it'll do the job. Bazooka tubes impress me none whatsoever, but they do provide more bass and a decent price. Now, if it were me I would look into some Infinity's running of a jbl amp
Say...Something like this...
Infinity Kappa 60.5cs (2 way Components) Run you 200....
Infinity from Thezeb
JBL P180.2 (90 watts per channel, 2 channel) Run you 170...
JBL amp from woofersetc.com
Then HU of your choice. Even that would be a very nice, moderate enrty level system. If you feel you need more bass, theres some good 8" subs to choose from, a veritable TON of 10 and 12"s to choose from. Problem is, you may have problems getting them to fit.