You can drill a 1/4 hole in each pipe without effecting the AFR to where it would register but on the same note a 1/4 hole isn't going to make the pipes louder. Once you get the hole big enough to change the tone of the exhaust you will have a problem with the AFR.

 

ican,&nbsp\\; You sound like you have been south before, so I am not telling you what to do, just relating what I did.&nbsp\\; I have a stock 2008 FLSTC.&nbsp\\; In April, I rode the Sierra Madres starting in Hermosillo to Chihuahua.&nbsp\\; Side tripped to Creel for two days.&nbsp\\; I had no problems with the gas.&nbsp\\; At one point, I even had to top off with regular because they were out of premium.&nbsp\\; I topped off with premium as soon as I could, but no problems.

 

Also, a 1/4-inch hole (or however many of them) will not really be a source of low-frequency sound. It may well end up slightly louder overall, but sound even more crap-like than stock to boot.