Turbos Leaking Oil... K04 or K03 Replacement?
 

I took my 2002 Audi A6 2.7t into the shop for leaking oil.. First time they replaced valve cover gaskets and it still leaked, took it in again and they said both of my turbos are leaking oil.. I'm going to pull the motor out myself and replace the turbos.. Should I go with the K03 replacements? And what brand should I go with? Or should I go with the K04's right away? If I go this route what else needs to be replaced in order for the engine to run properly with the bigger turbos and for the bigger turbos to fit? Thanks in advance for the response.