i switched to LED few weeks back because i had some heavy heat issue in summer with my HPS 250W, so i replaced it with a spiderfarmer SF2000 200W in my 90x60x180(2x3x6) tent.

for 4x8 i would go either with 2 sf4000 or better 2 se7000, se1000 don't seem to be adapted with your tent size imho