Hwy is no problem. Went from about 2700 rpm @ 70, to 3000 rpm. Plus I want to add a s/c down the road. If I stayed n/a I might have opted for the 4.10's, but then with the amount of hwy miles I do, it would have been annoying to say the least.
I noticed a difference in the performance from adding the x pipe right away. I put on a dynomax cat back to get the added performance without the noise. When I added the x pipe, it didn't make it so much louder as it made the tone more full. Got rid of that "factory" tone, so to speak.