I have a 2006 Ultra with a basic dealer set up stage 1. SE slip ons, air cleaner, dealer stage 1 flash. Would there be any gains by adding some kind of tuner? SERT, T Max, PC III? Or am I just better off leaving it alone? Power is pretty standard. Gas milageranges from low high 20'sall city to 42 highway. Any suggestions would be appreciated. Thanks.

 

I'd leave it alone unless you are planning other performance upgrades.

 

Here's the thing - the official download you get from a HD dealer must, by definition, remain EPA-legal. Said differently, your bike is still running a bit leaner than MOCO engineers would prefer, were it not for the need to meet those regulations.

A SERT or other tuner would allow you to richen the mixture a bit, albeit no longer being EPA-legal.

It's a minor thing, though. If your bike is running fine and you're happy with it I'd just leave it be, like Glideman suggests.