Help choosing a 400W HPS system

I was planning an all CFL grow but after reading post from experienced growers have decided HPS is the way to go. My grow tent is 32x32x63" and i have 4 little guys (AK4 in veg right now. Do you think a 400w HPS is the ideal power or should i go 250w or 600w? Also I not sure what the difference is between a stardard HPS and a MH bulb. Which would you prefer? I would like to find something with a cooling tube included so i dont have to worry about setting that up myself. Im not sure about some of the deals through small vendors and dont have a huge problem paying 300 - 400 through a reputable vendor.

If you were in my situation/budget what type, power, ect lighting system would you go with? Id rather spend money now then go cheap and have to upgrade later.

http://www.amazon.com/400W-Volt-Digital-Light-System/dp/B001GL03LS/ref=sr_1_8?s=gateway&ie=UTF8&qid=1285328140&sr=8-8

This link is to a 400W HPS system with cooling tube. What do you think? It comes in 120V and 240V for the same price, what difference does voltage make? I really appreciate you guys taking the time to help me out!!!

http://www.amazon.com/Watt-Cool-Garden-Light-System/dp/B001DYRC5I

Im also looking at this one which is a MH bulb and apparently has a superior ballast. What do you think?

I think a 400 watt system will serve you well. Most folks growing with HID lights use MH for veg and HPS for flowering in a perfect world. Either one will work for the entire grow. If I had to choose one or the other I would choose the HPS for the tent. I am not a fan of digital ballasts. If you buy a system with a magnetic ballast and the ballast fails, you can replace the ignitor and capacitor for about $47.00. The power supply rarely fails. When the digital ballasts fail they are junk and need to be thrown away. That is just my 2 pennies.

go to HTG Supply and check out their selection. I use a T5 system for vegging and 2-400 HPS for flowering

299$? Damn, give this one a look. It's 400w hps and 400w mh conversion bulb with ballast. It doesnt have a cooling tube though but you can add one. This is the one I will be getting soon. The difference between hps and mh is that you use the mh bulb for vegetive and the hps for flowering. Give this one a look:
http://www.htgsupply.com/viewproduct.asp?productID=47981

would a cooling tube fit inside the reflector?

I'm not sure, you could drill a hole if you wanted in the reflector and hook a duct up to it. My room is going to be 7ft high x 42" long x 23" wide with a 170 cfm fan so that should take care of all the heat coming from the light for me.

My room is just over 5 feet tall so i think a cooling tube will allow me to get closer to the plants in the later stages of flowering when they get taller and im running out of space. I have a few 125W CFL's for veg so i dont necessarily need the MH for veg but am not opposed to using one. I plan on adding a fan with a carbon filter to deal with the smell and am hoping that fan along with the cooling tube deal with the heat sufficiently. Id really like to get this right the first time around, its frustrating upgrading quickly making old equipment pretty useless!

Oh and do you know what the difference in Voltage provides? If the Watts are equal and one has double the Voltage what does that do? Thanks so much!

The voltages are for different power systems which can be regional. That just means you can use it on 120 or 240 line by setting the switch.

On another note, there are plenty of affordable air coolable lights that are not cool tubes. That is just one example. The reflector on a cool tube is pretty small. I have a 400 watt hps that you can air cool. It has 2, 4" flanges. One for intake and one for exhaust. I bought it used and the previous owner never air cooled it. It has tempered glass. Between the tempered glass and the air that I am pushing through the reflector, I was able to cool the room down by about 10F compared to when I was using just the bat wing reflector. Bigger reflector = more (better) coverage. I think my reflector (it is a nice one too) was made by Sun Systems. It happened to be the perfect size for my personal med grow.