For me it's two fold,

The whole driving experience with it's assault on the senses - noise, acceleration, grip and breaking. The way it looks and feels.

The other bit is the reaction of others to it, kids arguing over whether or not they know what it is. The 'Seat belt pads in mums Yaris with a Demon Tweeks catalogue on the back seat in McDonald's car park' crew who immediately start revving the nuts out of their respective cars as soon as they hear the flat four burble. The 'wtf was that?' reps in executive saloons who get left standing on slip roads and finally other real auto enthusiasts who are always up for a chat over the petrol pump.

 

i like turning petrol into lots of noise mostly :-)

 

The second turbo