I installed a new chain and sprockets yesterday, and put on a 16T front. Rode home about 75 miles from my friends place in PA to NJ on backroads and interstates. First gear feels a bit tall from a standstill, but more useful once under way. Everywhere else the bike just seems more relaxed, especially at speed on the interstate where it doesn't seem to have any problems pulling when turning at 4k and over.
I have the DNA filter, no snorkel and the S&S cans with the db killers in. I'll need to get to the point where I stop thinking about it and just ride it before I can really make any real determination as to whether or not I'll keep it on or go back to 15T.