Hi and welcome,
No experience of a 500 but the AGP is great fun. The only thing I've driven that grips anything like it on a smooth road was my old Lotus. I bought the AGP used, and the previous owner went for leather and the full aircon - good choices I reckon. My route to work takes me over 10 miles of poorly surfaced lanes and I wouldn't want the suspension any harder so think carefully about that kind of thing. More power is always welcome though... Re the pedal I find the AGP's a bit wide apart. Smooth heel and toe is challenge but I'm getting there!
For the record I also have an Impreza. Totally different experience and I can't see me parting with it anytime soon. Just goes over any kind of road surface with no bother at almost any rate of knots you want. You only know it's raining when you have to put the wipers on to see.
All the best, Trevor