That's expensive for a 400 watter man. I set the kit options (addons that you can purchase) the same as a 400 watt Ipower kit with HPS, MH bulbs, hangers, reflector, timer and two year warranty on ebay and the HTG kit you were looking at is 100.00 more even without the MH bulb.
I know people say Ipower sucks but you can get a full, ready to run kit on ebay for about 110.00 and they give you a two year warranty. It's hassle free, I've had to use it (after getting well worth my money out of the item) and they are real good about making things right.
If you're getting the same light penetration and intensity and you get a great warranty, you're just paying any extra for a brand. Check out hpsgrowlightstore on ebay, for the price of that HTG kit you could probably get a 600 or 1000 watter if you don't care about branding.