Congrats on getting everything working. My Spec Stage2 clutch started slipping about two weeks after I got my K04 installed. I would recommend Southbend for your new clutch. I don't think you should need a stage 4 unless you are going to get a bigger turbo in the future. Also I would think about a larger intercooler if you haven't already. Your car will still run well but it will work better with a bigger ic. You may experience limp mode issues in warmer weather and throttle cut. Run some Vagcom logs and you can see if this is an issue. It will be most noticeable on 3rd gear or higher long pulls. Several guys have turned in high 13's in the quarter with the same setup as you have.