I would go with APR, AWE, Revo or a name brand Audi tuner. Superchips has a somewhat questionable track record. You're problem is going to be the TDI. Most of the bigger tuners focus on the gassers. I googled "A4 2.0 TDI chip" and got tons of hits. Just do your research and get an EGT guage or you might melt your manifold. Good luck.
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