Tossed a hitch (Curt MFG) on my girlfriend's 2010 Mustang and a rack. Pretty damn happy. Still in North Carolina on vacation and it's quite useful.
Each time we go out with my friend's car down here with the bikes on her roof rack, I realize how nice a hitch rack is.
Went with the SportRack 2 bike rack. $140 from Amazon
http://www.amazon.com/gp/product/B000UUK276
I really can't understand buying a much more expensive rack than this. I did do two modifications to it:
1) Drilled/tapped for a small 10-32 internal hex cap screw on the bottom of each side bar so the wheel holders cannot be slid off. By accident or attempted theft
2) The middle bar can fold back to access the trunk better, I found it to not really be that helpful as it's easy to access the trunk. Installed a nut&bolt where the quick release goes so it's much tighter.
I locked the rack & bikes all together using a few cable locks and one kryptonite lock. One of the cable locks had gotten too close to the muffler and the numbers on the combo melted together. I figured I'd be out in my friend's parking lot for an hour hacksawing through it.
Less than 30 seconds with a hacksaw. Do not use cable locks kids. Eye opener. Glad I learned cutting it myself and not finding my bike stolen.
And I'm amazed at how stable the whole thing is at 100+mph.
-Steve