Used Cars: passat question, vw passat, fuel mileage

Question
hey jay im planning to buy a vw passat. i just have a question about putting a midgrade gas on a 1.8t passat. is it going to destroy and cause high repairs on the engine in the future? or is it just the performance that gets affected?

Answer
Just trust me when I say, use the recommended fuel.  Will it ruin the engine....probably not, but your fuel mileage will be affected, and would probably make up the difference you save in paying for the gas it needs.  You will definetly notice the performance.  Can you get by with it, probably, but it just is not worth it, in my opinion.  You will have engine pinging/knocking and it just really is not worth it.