What's the best upgrade option for a mid 2010 i3 iMac?

I know this is an old thread but I just picked up a mid 2010, 21.5" iMac i3 3.06Ghz. I know the recommendation is to only upgrade up to the i5 680 3.6Ghz as it has the same TDP rating as the i3 but I have two question, if anyone could help...

1) The i5 660 3.3Ghz is more readily available and cheaper, yet wasn't one of the original upgrade options. It has the same TDP rating and is socket 1156, do people think this would work?

2) If the reasons the i7 won't work is because of the TDP rating being 22w higher at peak, would it be possible to cut the power consumption from other components i.e.. Switch to HDD to SSD and remove optical drive completely to balance it out?

If anyone could give their thoughts before I start shopping for processors it would be appreciated.