If you are looking for a LED light and you want something that approximates a 400 or 600 watt HPS, you aren't gonna find a real system for less that the Procyon. Anything that you will find of the variety of the cheap led panels or the ufos have pretty much been shown to be useless cause their leds are too weak as any hydro store owner will tell you. The state of the technology is such that there are really only two products out there that really work -- procyon 100 or the ti-smartlamp 600 and its stronger 1000 watt version the Smartbar. If you take a look at greenpinelane.com you can see tests on all of them. The thing to remember about leds is that while they cost much more than HPS initially they payback the difference quite quickly, in 1 to 3 years depending on how much you pay for power and whether you need to cool, which you will have to do if you use HPS. They have a lifespan of about 10 years so the cost savings overall of LED versus HPS can be quite important, usually somewhere between 40% to 100% when you factor in the power savings. I switched to the Smartlamp myself for the powersavings once I was sure it could flower which it can since it is the only LED out there that i know of that has more than just red and blue leds. Good luck in your choice.

You really need to look at the photometric data for the LED you're planning to use. And then adjust placement based on your lighting needs/desires. Frankly, I'm of the opinion that too many cans can always be dimmed while maintaining placement. Realizing you don't have enough life after the fact makes for lousy can placement or a lot of work/expense rearranging things.

It depends on your lighting requirement per sq ft. Lighting the basement should be no different from other spaces in the darkest nights. Assuming that the space will be used as a general living space, 4 ft apart would work fine.

Isn't that funny? I was looking online on Ebay for just the same thing this weekend. The only difference is that I was looking for the type you suspend from the ceiling. My front porch has two windows that allow the full winter sun to come in but on either side there's a spot the the sun doesn't reach. My intention is to supplement those darkened areas to help the other plants get some much needed light. Currently I have a double light fixture with screw in fluorescent lights but they don't seem to put out as much light as I would want. Has anyone else used these high output LED lights and would you recommend them? My heart, prayers and thoughts are with all the folks in Florida that have been affected by Irma also. Fred