Help with a couple of problems 1.8t

[vroomtshh]

Recently had my car mapped and a new exhaust fitted. And having a few problems with it since.

I'm going back to see the mapper today and the exhaust guys tomorrow, but before I do, I'd like some knowledge to take with me.

Easy one first - my new exhaust is too loud (its a complete racket tbh but I'm sure you don't need to hear me ranting about it)
The standard system had 3 fairly hefty boxes. For some reason the exhaust fabricator decided that 2 would be better, even after I told him it had to be as quiet as humanly possible!!! The exhaust comes from the turbo, along the centre in one pipe, then splits off to either side of the car, with a back box just before each tail pipe.
Where would be the best place for them to position another box (or two) to reduce the noise.

Next problem, after mapping the car feels a lot more powerful (duh), but its actually slower overall to drive. I'm getting a 16683 fault code. Would a cheap diverter valve cause that code, and allow the car to lose boost over 4500rpm? Would it be so noticeable that in 3rd, 4th or 5th over 4500rpm, its like someone has a switch and is switching the power off and on?

Sorry for the long post, but the car is driving me bonkers at the moment

 

[jojo]

Could you tell me what model of Audi do you have, so I can re-direct your question to the correct section?

But generally answering your question, can't help you out with the exhaust, but second question, go onto the ross reck site and search your fault code brings up answers.

16683/P0299/000665 - Ross-Tech Wiki

 

[vroomtshh]

I'd prefer if my thread was left here, as its not specific to a model, but to an engine and there doesn't appear to be a specific 1.8t forum.

I've had a look at the Ross-tech site, it explains what the fault code is, but is very vague in what they symptoms would be, and what the cause would be