I drove both the Evo VII (not the VIII) and the penultimate WRX STi at Magione (Italy, short track) and althoung the STi felt
faster, I got the better times with the Evo VII.
Note, the Evo VII I had on that day had a adjustable rear wing whereas the STi had a fixed one, which might explain why I was faster on the straight with the Sti but way slower in the tight corners.
However, I still felt that the Evo was the superior machine, it seems the front differential enables you to "push" a little more when exiting corners. Can't somment on the seats because both of the cars I drove were equipped with racing Sparcos w/ 6-point belts.
Bottom line, it all boils down to your money and your driving style/expectations.
If you're looking to use it for track days as well as everyday driving, get an Evo.
If you're looking for those B-roads in the countryside, then get the STi.
I felt more in confidence with the EVo, but like I said; short track, adjustable rear wing and Michelins for the Evo and fixed wing (small one) and Pirellis on the STi.
Both had the following mods :
Sparco racing buckets w/ 6-point harnesses
Kingdragon RAM Air filter
Group N exhaust (but still w/ cat)
Reinforced Sparco dome bar
OMP Group N vented/grooved discs, OMP brake pads
Fly to live, live to fly - Air France/KLM Flying Blue Platinum, BMI Diamond Club Gold, Emirates Skywards