I suppose the better question is what programs are you trying to run in UAE? Will they run fine on an A500 running Kickstart/Workbench 1.3 or do they require an AGA machine with Kickstart 3.X or perhaps something in between?
If there are specific programs that need to work with the replacement kickstart it would be helpful to know what those are.
EDIT:
Replacement for UAE?? Like a ROM file for UAE.. Is this for ArosUAE?? Or is it a kickstart that boots AROS on classic Amiga hardware ( was 68K Aros Made??).. This really confuses me when I read this.. Do you intend on creating a kick.rom file that runs UAE that's made from AROS's open source kickstart (exec) routines? This is not very clear..
As I understand it, he (or she) is looking for a Kickstart ROM for use in classic Amigas (well emulated ones at least) based on the AROS sources. This would not be a full port of AROS to the classic Amiga (which I believe was started at one point, but was dropped and is far from finished), but just the subset representing the functions that the Kickstart ROM is responsible for.