Expanding.. Seeking advice.

Hi all. New to the site and somewhat new to the game.. I'm looking for a little guidance with my system. I run a KJ/DJ show at a local bar. During the summer, I play Wed. and Thurs. inside and Fri./Sat. outdoors. Wintertime, I fall back to just the 2 nights inside and occasionally a weekend inside. I have the opportunity to play private parties on occasion and could run sound for bands (with more equipment). I'm looking to expand my system to be able to accomplish all of this. I need to put together a system that can be split and function well both together or separate. Due to the nature of my gigs, I play a WIDE variety of music. The crowd also varies a lot. I play for anywhere from 30 to 400 people on any given night.

Breakdown of what I currently have:

Mains: 2 Peavey SP4s
Subs: 2 Behringer VP1800S 18" Subs
Monitor: 1 Kustom powered 12" wedge
Amps: 2 Behringer EP4000s
EQ: Behringer ULTRAGRAPH PRO FBQ3102 EQ
Mixers: 2 Behringer XENYX X1204USBs

The SP4's are a new addition. I replaced a cheap set Kustom dual 15's. I started off with inexpensive gear but I've been happy with most of it. The Kustoms were blown while I had someone running my gig for 2 months due to surgery. I started with these without subs and was happy with the value. They made a decent budget starting set.
I've been happy with most of the Beheringer gear so far with exception to the subs.. The system has been used 2 to 5 times a week for over a year now. The subs have just been "ok." No huge complaints there but no praises either. I've yet to have an issue with the amps, mixers, or eq.
I LOVE the new Peavey SP4s.. bit heavy though.


What I've been thinking of adding:

A pair of the Peavey SP2's. These would be used as tops when needed and mains for small gigs.

Subs-- I'm not sure. Either add to the Behringers or replace them completely. I'd like at least 4 that would work well together for larger indoor or outdoor shows but would sound well when split into 2 systems. I had been considering W bins (I looked at Sonics) but realized that I couldn't get the freq. response I want without adding at least 8. I'd really like to get down into the mid 30's. I would like to build my own subs(just because I think it would be cool..lol) but it's not a necessity for me to do so.

Amps-- Not sure here either. I've read so many bad reviews on the behringers yet I've been extremely pleased with mine. They were cheap.. I think I paid $300 for one and $250 for the other. I'll be adding to what I have but just not sure what I should go with.

Mixer-- Even though I haven't had an issue with what I have, I'll need an upgrade to run larger sound. I'd really like to stay with something small enough to be mounted on the top of a rack if that's feasible. What I've looked at are the 16ch mixers mostly. Most of the bands I've seen here (of the size I would be with) are using 12-14 channels. Mackie 1604-VLZ3 is an example of what I'm considering. Others would be similar size/features from Yamaha, Allen&Heath, ect. I would stay away from the Beheringer mostly due to the reputation they seem to have(but I'd still use the ones I have for my regular gigs..I like em>)

Eq's-- I'd add a couple more matching the one I currently use along with a DBX DriveRack PA.

Floor monitors-- I'd really like to 3 or 4 reasonably priced 12 or 15" wedges here just for ease of use.

My main goals:

1. A complete system to run sound for a few bands. My thoughts were 4 subs, the SP4's running mostly as mids, and the SP2's as tops.

2. The ability to split the main into 2 separate systems. SP4 mains w/ 2 subs and SP2 mains w/2 subs.

3. Larger outdoor events are fairly common in my area. Would I be able to build on this to satisfy that demand as well or should I look in a completely different direction?

What do you folks think? Any tips on the gear would be helpful.

Thanks!!