the answer is really dependent upon how your extractor is set up for the sc. Has it been tuned by a good smith who knows race guns? If so, all you may need is an adjustment of the tensioning.
Somebody school me on the difference. I have a gallon bag of .38 super brass some starline comp and other mixed stuff I've picked up over the years. I don't shoot it, and don't know. Its all the same length when sorting, so it all goes into the same container.
38 super comp has less of a rim than 38 super. 38 super TJ (Todd jarrett) has slightly less rim than 38 super comp (iirc). The two rounds with less rim stack better in the mag therefore allowing an extra round or so in the mag over plain 38 super. Most people use super comp from what I've seen. Although super is common too. An extractor had to be tuned to work with SC so it will catch the rim.