specs. 2000 Audi A4 quattro, 1.8t engine code ATW all stock except H&R Springs

driving down the hwy in 5th gear roughly 3500rpm. blew white smoke out of tailpipe and then more white smoke out of engine bay. got p0300 code for random misfire. coilpacks are good. car has 195k on it. all ive had to replace was the coilpack and sparkplugs along with routine maintenance
Blown Head Gasket??? or something else???

car rough idles like only firing on 2 cylinders. also was just a week away from replacing the stock K03 with a T28 because of shaft play and turbine fans clicking on inside of housing along with not showing a vacuum on my boost gauge. Any help is greatly appreciated. im used to building Nissans and Hondas. this is my first audi