yeah i bought the 89mm+outrunner combo from HC. The outrunner it comes with is ~1670kV and it's a bit of a no mans land as i dont want to run 5S (4S too low 6S too high).
i'm running this combo on an 1.6m F20 and i've pegged the max throttle in the tx to max it out at 1100W only as the batteries are two 3S 2200mAh 20C's and i don't want to fry them. once i have more flights on them i have plenty of battery room and i'm planning on 6S 2P'ing them and putting about 1.9kW into this combo on 6S. Not sure it'll work but i'll give it a go when the time comes.
I think for 4S i'd go for about a 2000-2200kV motor for about 1.0-1.3kW out of two 4S2200 for a total of 4S 4400mAh. You'd have high current and voltage losses though.
on 4S 4400:1.3kW 90A (safe option, should handle power, these motors get hot though)
on 4S 5000:1.5kW 100A (dunno, maybe too much power)
on 4S 4400:1.4kW 95A (but will probably melt)
When I melt the motor that came with this combo I'm going to buy one of these:
and run it 6S2200 1.25kW 20C or 7S4400 (lots more batteries) for 2kW
i have a lot of 3S2200's and 4S2200's so all the setups i have are multiples of these...