Ummm... Those sound like Piper marketing numbers. The fastest Archer I've ever flown, by far, was 122 KTAS on a really good day, and that was with the newer pants. Most of them are only 115 KTAS with pants, or 110 without any pants. I don't buy 125 KTAS for an Archer with pants, nor 120 without 'em, except in an exceedingly rare well-kept clean model.
Adding 180hp to an airplane that already has 160hp will result in a theoretical maximum of 4% speed increase, all else being equal. However, all else is not equal - adding a heavier engine means there will be additional induced drag from both the extra weight as well as the further-forward CG. If you want to go faster, an expensive engine upgrade is NOT the way to accomplish it.