I hope to eat my words on the S4RS vs the S3, time will tell.
With the Duc you should be able to get another 10hp just by adding exhaust and proper mapping. The testastratta motor loves large diameter exhausts. I have seen the 999's get up to 15 hp just from exhaust and mapping.
Theres very limited aftermarket support for triumph, especially in the motor department. Seems like if you want more Hp from your triple one has to turbo, supercharge or NOS there bikes. Non are my cup of tea.
It really is a hard choice if your not concerned with money but if you are the S3 is by far the best and most complete package.
