You might feel cramped if you are used to a large car like the GTO. You'll be giving up back seat usability too. Gas milage won't be better than 18mpg in regular driving. 0-60 times are around 4.7 - 4.8. It handles, well, like a sports car. It will get tons more looks than the GTO for sure. You might miss the v8 burble and roar though. Even the SRT6 sounds a bit like a vacuum cleaner or leaf blower.

P.S. If you don't already know, the SRT6 engine is hand-built by AMG in Germany. Everything mechanical on the car including the chassis is Mercedes and or AMG. What this means is a LOT of car for the money. It also means that parts are EXPENSIVE and usually have to come from Germany, maintenance is EXPENSIVE, and finding a mechanic certified to work on it correctly is a pain in the ****!! I change the oil my self, but if you don't, it'll cost you about 100 bucks. If you ever need to take your car in for repairs be prepared to be without it for a couple of weeks or at least be waiting for parts for a couple of weeks. Not a big deal to me since it isn't my daily driver. Don't be fooled, originally, this car was almost 50 grand, the sticker has fallen; however, the upkeep is still luxury sports car territory.