Any particular reason you are after an upgraded clutch kit? Looking to make some more power in the future perhaps?
For a stock 2.5DOHC NA I would just go with a stock Subaru Exedy unit. I would get the one right from Subaru (Subaru part number one) (via the cheapest means possible) as it has dual springs in the clutch disc as opposed to the single springs in the Exedy stock replacement (Exedy stock replacement part number and Subaru Exedy stock replacement are actually different). I swapped a EZ30D into my BK and went with a stock 07 WRX clutch and Exedy light weight flywheel and its great. No chatter, no heavy pedal or issues.

In regards to your flywheel I would bring it to a machine shop and see what they think. I would always recommend getting it machined although if you are on a super tight budget and there is no heavy burns on it you can clean it up with some scotch brite pads or a fine sandpaper and sanding block.

Ryan