Seems like many people are not happy with the termi exhaust.
What other options are out, and is there a way to tune the bike for this exhausts ?
Yes there are:
SC-Project - Motorcycle Exhaust System - Homepage
SC-Project is a world leader in the construction of exhaust systems for motorcycles. Italian excellence, from competitions to the road!www.sc-project.com
Motorcycle Exhaust Systems for High Performance Bikes
Spark is the Italian brand that distinguishes high performance exhaust systems for cars and motorbikes since more than 40 years.www.sparkexhaust.com
It seems no tuning needed. Check also vcyclenut on YouTube and his dyno runs.
Akropovic is also developing according their website.
...and, yeah, a proper map should make a huge difference.