I have almost 100K miles. Is it worth spending the money on the APR Stage III (or other big turbo kit) or should I take the same money as a DP on a newer A4?

tons of HP and torque is less fun when it doesn't go to the pavement... unless of course you enjoy burning through tires ;)

Its just means your driving style is different. I prefer AWD myself, but if dont mind delaying gratification until 2nd-3rd gear, fwd cars can be fun too.

Not to mention they are faster from a roll without the burden of AWD.

worth it just for the warranty.

left a nice burnout patch tho...