S3 Street Rat - a diet is not only good for handling, but is the best and cheapest power to weight mod you can do for your bike (and yourself)
My Tiger, would clearly outperform my older S3. The bikes are only 9kg apart (s3 being the lighter), but I'm now 40kg lighter than when I got my S3! I chose the combo of counting calories (using a website calorieking.com) and exercise (I'm bicycling at least 4 times a week).
If you can find a method that works for you go for it!
Russ