Good intro.   
Columbus Racing holds 2-3 private drag rentals a year. They are a ton of fun, even for the non drag guys.   
Also, lots of regular autocrossers here that do scca stuff, as well as the smaller clube events (Miata, Ford, Porsche, etc).   
A handful do HPDEs as well.   
Details on the mods on the A3, brand, tune, etc?