Looking into german cars

I really like the idea if getting an audi if not a bmw

I plan on modding the car and want somthing that can get up to 500hp Sedan or Coupe, doesnt matter Auto or Manual, doesnt matter Id like to get a car that weighs less than 4000lbs and have 20k maybe 25k to work with for the vehicle not including mods I can do mechanical work on the car and have access to a shop with any tool and vehicle lifts if that matters to anything really just needing a car with more space than my 370z