As somebody who set up a beginners studio recently, please allow me to give you the benefit of my experiences.
First, understand that studio equipment, especially the lights, are a system, just like your camera. Accessories for one brand, do not necessarily work with another. And trust me, you WILL be buying accessories. "Studio Gear Syndrome" is as bad as LBA.
First, make sure your lights all use the same accessory mount, AND there are plenty of accessories available in stock at your favorite dealers for that brand. Living in metro NY, you are lucky in that regard. Lots of good pro photo shops.
My B & H Imapct kit included 2 300WS lights and 1 160WS light. The 2 300's use a Bowens mount, and the 160 uses an Elinchrom. This is bad in that I have to duplicate things like softboxes or filter holders or barn doors for each type (or get an adapter if they are available). The second problem is that neither of these brands are that popular in the states, so accessories can be hard to find.
If I had it to do over, I would not buy a ready made kit. I'd buy individual components. It might be more expensive up front, but more economical in the long run. I would also recommend that your lights be all the same power. It just simplifies the math when figuring out your lighting ratios.
Start small and build up. Just research your system choice first and stick with it.
I noticed your choice of gear is continuous lighting. Probably because of a low initial price if I'm guessing right. It is a false economy. Umbrellas and softboxes, and gel filters, or anything you put in front of the lights, all need to be rated for hot lamps. Rated accessories are more expensive.
Here is another option for you. Go over to Strobist.com and read the site thoroughly.
For close to what you wish to spend on hot lamps, you can set up a system consisting of a pair of Vivitar 285HVs, stands, a couple umbrella adapters, a couple of shoot through umbrellas w/black out covers (they double as makeshift softboxes, an optical slave and the Pentax off camera PC adapters and a long PC cord. You can buy the Pocket Wizards when you get some cash. This set up has the advantage of being expandable, portable, and usable. To expand you just need another 285, cheap optical slave, and a stand. You can also make a lot of your own accessories, like barn doors and snoots. A little Velcro goes a long way. Foam core board makes great reflectors. I use white silver and gold. The only real downside to this is the 285's longer recycle time compared to studio units. Still, great for learning.
The links below are some examples. You could probably do better in price if you searched harder. This outfit would run you $330.00 or so. A bit more up front, but infinitely more versatile. It may not be exactly what you are looking for, but I'm just trying to get you to think of alternative possibilities.
Just my thoughts on the matter. Hope this helps some.
Vivitar | 285HV Auto Flash | 233965 | B&H Photo Video Impact | Digital Flash Umbrella Mount Kit | B&H Photo Video Hama | Hot Shoe Adapter 1 | HA-6951 | B&H Photo Video Paramount | PC Male to PC Male Cord | PMB6C | B&H Photo Video Hama | Hot-Shoe Slave | HA-6967 | B&H Photo Video