Would changing exhaust systems require the ignition timing to be changed?

[Yo J]

Say I am running RH TD on my 06 Ultra with TMax... and it runs awesome! 

I have a chance to run a 2:1 exhaust...

I know the TMax will take care of the AFR....

Would changing exhaust systems require the ignition timing to be changed?

[Yo J]

ANY alteration you make to your engine, intake, exhaust or fuel requires a different ignition timing. Worse yet, a different advance curve is also required. ....

http://mg-tri-jag.net/tech6.htm

[PC_Hater]

Well, sort of.
If you want your engine running as well as it possibly can under all circumstances than you need something that lets you control fuel and ignition timing very accurately under all conditions.
Fitting the 2:1 on your bike will not require changes to the ignition timing. However, you are running True Duals - a different exhaust system from standard - did you change the timing for that? No. Yet the bike runs 'awesome'. Are you now going to worry about it and remove the TMax and fit something else? No.
Fit the 2:1 and let the TMax do whatever it does and don't worry about it.
If you build a fire-breathing monster that is the time to start worrying about ignition timing changes.

When my bike finally gets on the dyno the only reason I will make them check if the ignition timing needs changing is because it has PCIII and that lets you twiddle ignition timing.