I get 18-19mpg instead of 25-26mpg now... so there's that. It's $300/yr more expensive to insure (your results may vary). Consumables do cost more and you'll want to find a good independent Porsche technician to work on it if you're not handy turning your own wrenches. Obviously you shouldn't trust it to the minimum wage teenagers at Jiffy Lube (not that you should trust your FR-S/BRZ to them, either!)
If you buy a 996/997.1 or Cayman/Boxster with the port injected engine you will want to replace the IMS bearing if it hasn't been done already. The part itself is ~$800 and to pay someone to do it you should budget $2000 including the part. You shouldn't need to do it to the 996/997 Turbo or the 997.2/Cayman/Boxster with the direct injected engine. They are also known for cracking the plastic coolant expansion tanks which can be a bit of a PITA to replace; they turn yellow and crack with age. It's usually good to replace it, the water pump and thermostat all at once if you're dealing with a ~10yr old model. They're also known for having a wire off the alternator that's too small to provide sufficient grounding and it causes voltage drop and hard starting when hot. My car has this problem; it's $99 to fix through Suncoastparts.com
Had my 997 for three weeks now and I haven't looked back (I do miss the gorgeous Galaxy Blue color vs Arctic Silver, but that's it). I got invited to a Porsche driving experience at Thompson Speedway this past week where I got to thrash my 911 and a brand new Cayman S and Carrera 4S on the track; it totally validated my purchase! I have autocrossed my BRZ and driven a GT86 on the Nurburgring before and needless to say the 911 was much more satisfying to drive at the limit (assuming you have the driving skill - the BRZ is a better beginner's car). That being said, the consumable costs associated with racing a 911 are going to be higher than an FR-S/BRZ, stock-for-stock and mod-for-mod. You'll find that mods for the 911 cost as much as double, sometimes triple what they would cost for your average Japanese tuner car (I have no plans to modify mine like I did the BRZ; perhaps a set of OEM X51 headers, Fabspeed cold air kit and a Eurocharged ECU remap to bump the power up to ~380hp).
The 911 is also a much more pleasant car to daily drive. It has a slightly quieter cabin, considerably better stereo, less-notchy shifter, nice exhaust note, better steering feel, and of course, more power and torque. It's less twitchy on the highway and the suspension is slightly more composed although the fat rear tires do crash over bumps and tramline slightly on uneven surfaces. No bluetooth, nav, or satellite radio sucks but I plan to upgrade the head unit in the future.
I don't like the key being on the left hand side of the wheel, though! It's much more logical to insert the key on the right while you close the door with your left hand... Oh well; that's not going away anytime soon
