Whilst a remap may only give you 15bhp that is not the figure that matters.
You will find that by getting your car remapped, you will produce a considerable amount of torque a lot lower down the rev range.
This means that your call will pull like a train, and to be honest the larger the engine, the more noticeable the difference will be.
Audi have designed the V6 engines to be smooth and silky, and there is a massive improvement on tap, as out of the factory the engines are not realising their full potential.
I have a 3 litre A4 TDi Quattro and got my car remapped earlier this week.
I was totally shitting myself about spending so much money.
I am a pesimist by nature, and never believed that a remap would make much difference.
My only regret now though, is not taking my old BMW 330d for a remap three years ago, and I am kicking myself for that, as I had three years disappointing motoring whereas I could have been driving around during that time with a big grin on my face.
Seriously... just get it done. I promise you won't rgret it.