I like SLK 230 and 320. If we are looking for pure sports car feelings, all the car we can afford can not make it. I agree with you that for 230, it does not look so good when it is covered. but for 320, it looks nice in both converted and unconverted style.
350Z has a very nice design, but for mechanical part, I do not think it can fight Subaru WRX. WRX might be the most sports-feeling car in the affordable price range.