leasing a car is just throwing money away. With the amount of money you'd lose, you might be able to add some luxury to the STi and have the best of both worlds.
Things you can do to add a touch of posh to the car:
-leather performance seats from Sparco
-in dash DVD/Navi unit,
-carbon fiber interior pieces http://forums.nasioc.com/forums/show....php?t=1328087
-while it is sacrileage, you could get a second set of rims with higher profile/more comfort-based tires
-in car adjustable coilovers