I first bought my A4 in March of 2012. By August I had added the APR chips to it. I wrote before that the first thing I would upgrade was the suspension. I think I was wrong. One problem few people talk about is how sluggish the A4 is in 70+ degree weather. It's so bad it basically eliminates any gains felt by the APR upgrades in the first place. As soon as the outside temps get under 60 you'll think you got a brand new car.
So, now I'm rethinking my strategy again. It's not that the APR upgrade doesn't work as promised, it's more like the Audi under-performs in summer so much, that I really should have addressed that first. Possible solutions would be the APR/Carbonio air intake, as well as upgrading the intercooler first. Then the suspension, and finally the APR chip upgrades.