For those who have been wondering and debating how much does the stock EX rims, HFP rims, Si rims weigh, I finally found a vid from College Hills where they did the weight test.
Note: I believe these are 2006-07 wheels, and I don't know if the TPMS adds anything
http://youtube.com/watch?v=IPSz8B4X2KI
HFP 16".................18 lbs
EX Stock 16"..........20 lbs
HFP 17".................20 lbs
Si stock 17"...........23 lbs
HFP 18".................23 lbs
Mugen 18"..............16.5-17 lbs
This should help everyone who's been wanting to lighten up for summer or the track.
Cheers.