There are a couple of exhausts that do away with the tips. As much as I disliked the tips before owning the car, once I realized they serve a purpose and I saw them every day I came to like them.
The main things to consider between the years are the newer instrumentation (old: equal sized tach+speedo, new: big tach centered), the LED headlight strips (which does away with the headlight turning feature), and the suspension tweaks in more recent years.
Coming from a MS3 you will enjoy any year ISF. With my background in Mitsu/Subarus with coilovers, I don't find the 08 ISF to be as harsh as people claim. It's certainly not an idea setup but you shouldn't have any complaints. And I got a steal for my 08 so there are some nice deals out there.
Steve // 2008 IS-F / Starfire Pearl / 65k miles / Tint: Front 35% Rear 20% / JoeZ PTS cat-back exhaust / Beat-Sonic Nav+DVD bypass / Vaistech SL2Vi iPod integration kit / carbon fiber de-badged front grille / carbon fiber vinyl on lower rear bumper / S4Play rear diffuser / Escort Passport X50 / 80GB iPod in the armrest //