You plan on using T5's or CFL's?
I have my plant surrounded on 3 sides with CFL's, plus the ones above.
Flouro's don't give the penetration of the big boy stuff, so more IS better.
400 watts of hps stomps 400 watts worth of cfls or flouros anyday. go withe the big boy bulbs and you wont need side lighting. look pon craigslist for a used 400 watter. cost you about a hundred bucks but your yields will be worth it. about 3+ times more worth it.
if you spend 30 bucks on an hid system its junk. but a hundred bucks or so should get you a ballast and older air cooled hood and bulb. but it gets you on your way to better buds and yields. i repeat dont spend 30 bucks on an hid system. also avoid wire it yourself ballasts. most people fuck the wiring up. a good hid system will run about 300 bucks new just for the hood and ballast minus a bulb. unless you order it online. then you save a third on equipment costs when buying new. craigs is a good place to get used cheap stuff.