eddie jr

Have some questions and would like some opinions on improving the sound system given the following constraints....i have picked up the UQ7 performance sound system (firebird) and do not want aftermarket large amps and subs laying around, as I prefer the clean look for the car.

So I was wondering:

1. What are some really decent 4x6 replacements (or can you even put round up front? Would round over oval really matter?
2. I noticed there are some 3-way 4x6's but not as common as the 2-way. Are the 3-ways still going to be a bit better (although I am sure they don't cover the low end as good as a 6x9).
3. Does the amp in the UQ7 system have built in crossovers to only send the low frequencies to the small subs or can I add caps to do so??

Any suggestions would be appreciated,
thanks.

eddie jr

anyone?