What about the 350? Real world performance between the 500 & 350 isnt very much at all. I've driven many of them. 500 = more power, more torque, more weight, more bills, plus the dreaded ABC suspension - pump £1000, valve unit £1000, struts £1000(each)...... At least one of these WILL go wrong. 350 has normal shocks/springs, a bit less power, more agile. 272 & 273 engines all suffer from balancer shaft problems, not a highly common thing when concidering how many they made but costly repair if needed. There is a chassis/engine date after which you're safe though, some time in 2006 onwards. SL55 is a pretty strong engine, likes visiting fuel stations though....