Exhaust
Don't know what you are looking for in an exhaust but, there is a bunch of options out there...look for a while before you buy. Do you want loud? Soft thunder, long, short, radical, old school. Look around at other bikes and talk to owners. Most will love to tell you the story of their exhaust, or any other part of their bike.
The exhaust install is not all that bad. Just be patient and determined to get through it. Or find a friend who does this type of thing and have them help you. Prices on exhaust can vary widely so, look around before you buy.
I once bought a set off of ebay, they were used and had a few small scratches that were only noticed if you laid on the ground to see them. Anyway, shop and ask around...$150 including shipping.
The module is out of my option list. I just rejetted the carbs and have had no problems. Good luck, safe riding.