Well, for a start there are many games that won't run in WHDLoad *without* extra memory, so in that sense, yes, the extra memory will help. WHDLoad is very good at getting games to work on 030 CPUs which otherwise would crash. It also helps when you have a newer kickstart than the original machine came with, but I'm not fully sure what you mean when you say "without the need of an earlier kickstart" - have you upgraded the Kickstart in your 600? Because the stealth accelerator won't affect your kickstart...
