Wow...that's quite the nice complete set-up. Not sure what it would cost to source all those items separately...maybe quite a bit less $ but more hassles. You'll definitely get your feet wet and learn a lot for next time...which is ALWAYS the case no matter WHAT you start with.
The only "issue" I see is the yield they claim..and the yield you're after. Typically, a pretty respectable harvest amount is 1gram per watt of light. Some people get less some get more. A gram per watt is not always EASY but is a good number to shoot for. Oh..FWIW, a 400W makes fewer lumens per watt than a 600 or 1000 so 1g/w might be a little more tricky with 400 watters. So yeah...if you assume 1gram/watt and if that tent comes with 1200watts of 400watters...IF you managed to get TWO grams/watt that's still only 2400grams or 2.4Kilos which is about 6elbows. I think they were saying you'd get over 12pounds with these 3 lights??? I'd say that's pretty much impossible unless you bought your seeds from beanstalk Jack.
I think it's kinda shitty that they market this system like that. I'd say that 99.9% of people (no 100%) who buy that system are gonna be in for a big letdown. I don't know of a person on the planet who can get more than 2grams per watt from 400watters..or 600 watters...or 1K. Not saying it can't be done....just that most people buying this complete pkg will not come even close to the yields these guys project. I'm assuming that most buyers of this system will be entry level growers. Just another reason I say that NO ONE who buys this system will be able to realize the yields they claim.