2x2.5 in no way should exceed 6 feet, up to 8 is great but for that small of a footprint you won't need the height... I have 2 newish grow tents, 1 a gorilla 4x4x7'... It was like almost $500 by the time it was shipped.... The ceilings where I moved to are. 6'10-3/4"... A no go so take ceiling height into account... You need a good 8-12"s minimum extra to get the tents put together and upright... Even with regular 8' ceilings I had a tough time setting it up... If your going with anything less than a 4x4... 6 to 7 foot should be more than enough... Honestly I like my 3x3x6 jardin... If it was any taller it'd be useless space... I guess if you had to put a stink filter and fan in there to the head height wouldn't hurt so u could put the filter and fan above the light...
Are you talking about this???
http://www.growboxusa.com/cart/grow_tents/2.5x2_grow_tent
In no way should u be paying $1600 for that... If you have enough know how to grow herb, you can buy any tent u want and set it up the way you want primo for $1600... I love the quality of my real deal gorilla tent but after buying one I would only be buying the gorilla lites for the foreseeable future... Too much $$$ that could be better spent on other grow room needs.... I doubt a regular gorilla tent will give u double the life of a gorilla lite or any of the upper tier name brand tents out there...secret jardin, gorilla lite as I mentioned... Gorilla does make the best tents hands down but like I said a gorilla lite is better money spent for someone looking to get started... If u wanna save $ or time on turnkey shit; I'm sure eBay has a bunch of turnkey setups with less bullshit for cheaper...
The light('s) I couldn't tell u the first thing about.... every time I get the urge to buy an LED I don't feel confident they'll be on par with HID... I still buy Hps or mh.... I've been eyeballing galaxy's digital ballasts as of late... I think one or more of those will be the next ballasts I buy...
The c02 system is bullshit... Either go with tanked or a burner but honestly either way I'd advise against c02 for anyone newish to this... There has been zero mj related deaths, but there have been plenty of c02 related deaths... It's something for the advanced grower who has plateaued with their strains and can get the extra out of it... You can yield plenty without c02.... When you've pushed the same strain multiple times and can't get 1 more gram out of your setup....then invest in c02... By then you'll know what u need and what u don't... I'm eventually gonna bite the bullet and run it but I'm not there yet.... but it's one more thing to go wrong imo.... Start simple, it's gonna get complicated enough before you know it...
But I can't see it bro... Each time I go back and look at it again the more I see that is a waste of $ or $ that could be spent on better setups... Literally your getting an awesome tent filled with a Walmart tote with water heater insulation on it, most likely Chinese led's and half ass everything else... Even if it cost u a few more $'s to do it yourself I'd still say don't do it... If that's what your willing to spend, spend some time and find a site (I like growers house.com) and sit there n build your system the best u can, use that turnkey setup as a template except ditch the led's and get a 250-400watt hid hps/mh digital ballast, bulbs, and air cooled reflector....
The way you grow will dictate your setup... I'd say get a 3x3 or 4x4 tent (if u go with a bigger tent you may wanna up the light to a 400/600 for a 3x3 or 1000 for a 4x4) and grab a flood and drain table (make sure actual dimensions of the tray fit in your tent, there's 3x3 and 4x4 tents that are those dimensions inside to hold a full on 3x3 or 4x4 tray and then there's tents that the outer dimensions are 3x3/4x4 along with trays to fit those tent sizes; very confusing at first... Just make sure the tray is gonna fit the tent before u buy either that's all..I.e. check inside and outside dimensions of both.)... From there pick your poisons... Net pots, square pots... Medium('s), nutes... Figure out your desired medium before u pick your containers... Smart pots are awesome for perlite but plastic pots of any sort are better used with hydroton or similar media that isn't gonna clog your lines, pumps, pump filter bags etc... Found that out the "almost hard way"... Meaning I bought perlite to be used with 5x5 square pots for a flood and drain table and then realized it was the extra fine perlite so it woulda been all in my system giving me headaches but double checking everything before I fired the system up saved me and I ended up picking up some hydroton and grow stones for a mixture... If I was to do it again id probably just stick with one or the other...
But yeah... Spend your $ wiser... If it's no object, fuck it... Go for it... but I'm fairly certain you'll be disappointed in everything except the tent... That's about the only thing I see of any real value aside from it being "turnkey"... But your paying for someone's time to put that stuff together when u can do it with better items with some time and thought... That and 15 year expectancy isn't realistic, maybe for the tent if you were the most gentle person on the planet but everything inside that tent will most likely need replacing in less than 2 years of continuous use.... Good luck... I'll try to answer anything I can for u... I'm no amateur but definitely not a pro yet either...