If you have even moderate swirling, I'd say you will be fine with the 105. Again, on a 2 year old Black Sapphire car, it's unlikely it will be too aggressive. However, if you care for the paint properly after this detail, you shouldn't need to use the 105 again (or at least, not for a long time).
The 105 followed by the 3M Finishing sounds like a good combination to me. The 3M sounds like it would be comparable with Megs 205.