I had a lot of bad swirls, scratches and marring on my 1999 black Camaro SS. I hit it with 105 and a yellow foam pad on my 9227 but wasn't getting much or a result, so I hit it with a Medium compound and a wool pad and now I have to polish the marks from the compound. I buying a 6" Griot's DA and I'm thinking about using a Menzerna or Pinnacle polish(swirl remover).
Menzerna SIP, 203 powerfinish and 85rd are three great polishes. Meg 105 is great to have on hand and Prima Swirl is fantastic cuts like SIP littles less finicky and finishes down great.
If you weren't getting results with m105 and a yellow pad there's something wrong lol. I use either m205 or Menzerna power finish for my final polishes.