I've read a number of posts on this site in regards to the deposit issues with VW 2.0T FSI engines. My friend's VW 2.0T FSI has 20k on it now and it's probably a good time to use a quality fuel additive. He always uses top-tier 91 octane fuel, so I hope the deposit issues aren't too severe. Pep Boys has Techron Concentrate Plus on-sale for $8 (Buy One, Get One Free), but it's the version that treats 12 gallons. Should I just dump 2 bottles in there? The GTI has a 14.5 gallon tank. As an alternative, I could use the Redline SI-1. I used a bottle of SI-1 in my Saturn and in a Corolla, but I didn't notice any difference, so I'm a bit skeptical. I don't see many Techron fans on this site. Is there a reason why? How does the Techron Concentrate Plus compare to the Redline SI-1. I heard that the Techron was recently reformulated. Thanks!