Here you will find information about some of the modifications/improvements that I have done to my Caspian Blue (maybe not the fastest color) 2006 Triumph Sprint ST. Most of it will be applicable to many other motorcycles.
First, I installed heated grips. I used the Hot Grips kit and a Heat-Troller to control them. The addition of a relay to control power to them completes the installation. This is a good introduction to both products even if you are installing them on a totally different bike. Read about it here.
Next, I installed a customized mount for my Garmin Zumo 550 GPS unit. I used a little piece of aluminum bar stock and the bolts that hold the handlebar on to create a slick, inconspicuous and very functional mount. Very little skill is needed to do this nifty mount. Read about it here.
Last, I found a defect in my bike – the clutch cable gets a hole rubbed in it by a support loop that has a sharp end. This might save you from a surprise clutch failure. Read about it here.