Hi,
I have done this a few times for clients over years on these specific parts. I have moved them to the GNU compiler and it proved effective and cost efficent. I can only speak about GNU gcc because this is what I focus on so using Codewarrior maybe possible but a Codewarrior user would need to speak up.
The GNU gcc is nice because it has moved over the years with host operating systems, be it Windows, Linux, or MacOS. Sure you may need a new build of GNU gcc for a new host but your appliction source code does not change greatly if at all.