I have no experiences with the KUL Renaissance but I can comment about getting around without a car:
- walking is ok for many distances. But be aware that it's humid.
- there is a very convienient subway. It covers only a (small) part of KUL.
- taxis are cheap. The later the day, the more taxi drivers rip you off.
(In case you are interested in reading a part of a trip report and some pictures from KUL: see
http://www.flyertalk.com/forum/Forum81/HTML/003080.html and go down to the section about KUL.)