Well I don't have a 05-09 car so I can't personally tell you which setup is best. The +05's have a different suspension setup compared to the pre 05's, and I'm not too familiar with that setup.
But I can give you some advice based on my experience with lowering.
If you are dd the car on highway roads I would consider a mild suspension setup..something that lowers the car but doesn't slam it. 1-1.5" vs 1.8-2". Also I wouldn't remove isolators and choose extremely stiff springs.
I only drive my car on weekends/nice days 7 months out of the year so I slammed mine and went with stiffer springs. I did take the car on trips a few times with it lowered and the ride was harsh on rough roads and over highway bumps. I wouldn't recommend an extremely low and aggressive setup for a dd car.
Coil overs are really nice since you can adjust them, however they are more expensive. When coilovers first came out they were stiff and primarily for road coursing..but nowadays most kits can be fully adjustable yet still provide a comfortable ride. So don't rule them out completely when it comes to ride comfort.
I'd suggest a set of mild springs with a 1.5" drop would be a nice drop for a dd car. The 05+ still look real good with a 1-1.5" drop.
If you want to take the car to the track/road course on weekends look into coil overs. Expect to pay more but you'll enjoy the adjustability of the coil over shock setup. Raise it some for the drive to work, lower it for the aggressiveness of the road course