I recently purchased a 2007 A4 Avant with 165,000km; it is Quattro and has a 6 speed manual transmission and as far as I know 100% stock. I have a fun summer car and a motorcycle so this one is for commuting in the winter. I want to keep this car for a long time and I don’t know how much maintenance the previous owner did. There are some things that need to be fixed, as is with most used cars. There was no skid plate so I bought an evolution Thor kit

Evolution Thor Skid Plate For Audi A4 & Audi A6

I also need new wiper blades and some touch up paint. I think I have to go to the local dealer for these things and while I was there I want to ask them if they can look up the service history, or do I have to find the original dealer that serviced this car? I really want this information so I can get a baseline on what has been done and what still needs to be. I plan on replacing the cam follower as well because all I read on these forms is that it needs checking every 30,000-50,000km and they fail often. I plan on changing the Diverter Valve and replacing the PCV with the one from BSH, however I am confused on how this works and can’t find much info on it. They also sell ones with catch cans and those look like much better products. I really don’t know what is good as this is my first Audi and I don’t know anyone in my area that tunes/works on them. I looked around and found that AWE sells a “performance Diverter Valve” is this one the best on the market or should I just go with the OEM piston DV.

I also think I am getting bad gas mileage and one thing I do to all my cars is put new spark plugs and ignition wires/coil. As for spark plugs I have always been a fan of NGK platinum but I hear lots of good things about E3. I have read a bit but can’t really pull any real answers as what is the best for a stock engine. Any way back to the main topic of preventive maintenance other than checking the cam follower, regular oil changes, keeping the car clean is there anything else I can do to make this car last 300,000km?