I'm using GReddy, it has heaps of features but is a bit of a pain to use (just trying to push 2 or 3 buttons at exactly the same time), I can't seem to calibrate it right atm, but when working properly is pretty good.
Has several different timer settings including a calculating one which monitors how hard you driving and recommends a cool down time, also has lap timer, 0-100kph 0-200kph time, 1/8mile and 1/4mile timer, voltage meter, speedo, RPM display, not sure what else but heaps more than I ever used.
oh, And Welcome to the forum, I'm sure you will find all your answers. Do a search and you will find heaps.