I would definitely say go 2010+, very glad I did. Hell, if the price is right, I'd sell you mine
2010's don't seem to have diff pin issues and they have way less clutch master cylinder failures. I swapped out my fuel relay for the updated one the day I bought my car so I can't comment there. The better factory tuning in the later years is irrelevant once modded & tuned. 2010+ has a few small, but noticeable, improvements to the interior.
I added 20 sq/ft of sound deadening to my car and it really helped; the car is just fine on the highway for long trips. I also added Presto adhesive felt to the backside of a lot of the interior plastic to reduce the rattles and squeaks.
If you opt for the SST transmission they are able to hold power very well assuming you have it properly tuned, and buy the appropriate clutch packs for your power goals. If you plan on upgrading the turbo, plan on upgrading the SST clutch discs. Also plan for annual fluid and filter changes for the SST. SSP makes a decent OEM replcement paper filter for $50 (Mitsu is $110), but I'm not sure what the Diaqueen fluid costs these days.
The only major problem I've had with my car was the transfer case being overfilled from the factory causing it to grenade at 13k miles; brand new replacement was covered under warranty though. Otherwise, the car is holding up really well, including my stock clutch still. 425whp/400wtq, 27psig, 93-octane, 54k miles.