Just installed vance and hines big shots on my 2008 dyna super glide custom. Soon to put aftermarket air breather. Dont know whether to spend the $ on a power commander, V & H fuel pac, or just do the harley download.

Hi, Litebeer_99 the answer to this question is way above my pay grade for this situation, I would call or visit my local dealer or reputable shop's service/parts department and enquire about any possible quick fix, answers, or parts enquiry.
For more information about your issue and valuable "FREE" downloads that you will need for viewing or printing please click on the blue links below and for more specific information or questions at no charge please feel free to contact me at [email protected]. Good luck and have a wonderful day.
https://www.v-twinforum.com/threads/2002-dyna-wide-glide-88-problems.338722/
http://www.mediafire.com/file/n32mo9rud2vadf4/2002_Harley_Dyna_Service_Manual.pdf/file
https://partsfinder.onlinemicrofiche.com/ronnies/showmodel.asp?make=hdmc
http://mybikemanuals.com/harley-davidson/harley-davidson-dyna-glide-owners-manuals/
https://www.6ya.com/how-6ya-works to speak to me personally.

There are many to choose from. I have to like "Vance & Hines" or "Rush" brand of mufflers.

Honestly the best way to do it is t get the bike on a Dynomometer and have it adjusted that way to assure your HC (hydrocarbons) are in the 14.4 range, plus they can make sure you are getting the maximum horsepower out of all the money you put in to it.
Typically for the cost effective way is to get the disc or go to VH's website and see if you can download a map from there, but sometimes these can get you close, but not optimum.

If you send them a request for the map, they will usually make one for your model and description. They aren't that big of a company. They have 3 dynos, and 1 - 2 techs that actually make the maps. If not I would look for a map with the V&H big radius or staggered drags.

I’m happy to assist further over the phone at https://www.6ya.com/expert/robert_5bac37c3cb991fdb

go to their web site. There is a little more to this unit than just setting it! There is a multitude of values that can be put into the unit. They have instructions on the use of this unit and can match your settup with the proper values

Depending on the pipes you purchased, they will be stamped as to whether or not they meet noise requirements. Many if not most aftermarket pipes do not. Sorry.

Whenever I have a question about an aftermarket part - I contact the manufacturer, they are very helpful, but to answer your question, In general, if u get the correct part for your model bike, it should mount the same as the OEM part you;re replacing