+1 on the 5th gen maxima. I had one for 7 years before buying my BMW. If you can find a 2003 maxima 6 speed, that will get you 0-60 in 5.9 secs. You might be able to find an Infiniti I30/I35 within your range too. Not sure if the G35 is down to $5k used yet.
I also had an MR2, but it was a 3rd gen, so not the same. That car over steered like crazy but was a blast. It felt a bit flimsy though, couldn't get past the body shake and the wind noise at high speeds.
2009 335i 6MT M-Sport AW/CR Convertible
2002 Toyota 4Runner 4wd