Will opening a German bank account affect my TESA?

A friend of mine (who is also TESA) is leasing a car from Audi using his German bank account to pay the payments and German insurance. He'll have German plates on his car (because he's leasing the vehicle) and USEURAR Heidelberg told him he'd be ok to get gas coupons and everything. Sparkasse Neumarkt told him all he needs is to set up steady deposits in his account (3 back to back paycheck deposits) and he's good to go for anything from a EUR130,000 Audi R8 to a house. Is this right? Isn't this going too far and will be flagged by DOCPER? I've heard just registering in your town could cause you to pay taxes and lose your TESA. Then again, I know people who have TESA and also have German bank accounts and German property. It's always a grey area for us contractors as for what we can do and can't do.

Could getting a German bank account and going the same route with a car affect my TESA? How about getting a loan from a German bank? I hear the interest rates are very low. Anybody here TESA, has a German bank account and regularly use it?

Thanks!

http://www.toytowngermany.com/forum/index.php?showtopic=137283

Looks like this topic already answers some of my questions. Sorry people.

But I'm still curious about loans. Any TESA people ever take out a loan at a German bank?

Someone my Husband works with leases a German car, not sure how he pays for it but he's been doing it for about 5 years. We have a German bank account to pay rent and bills and it's never been an issue, but we pay cash into it every month, never had the paycheck go directly into it.

A german bank account and loan from a german bank won't affect docper/tesa status.