This is not aimed at anyone in particular, but it irks me to hear about people with non standard cars complaining that its audis fault when they dont work properly.
I might be accused of being a bit simplistic here, but If you have a misfire and your car is absolutely not modified in anyway then take it back to audi and get it fixed under warranty (i know they may have trouble diagnosing, but they'll get there in the end, even if it means an entire new engine).
If your car is fine in standard trim , but misfires when remapped, then its the map causing the misfire. That doesnt mean that the map will cause a misfire on every single s3 and it doesnt mean the map is faulty, but just that on your particular S3, it causes a misfire. It isnt because you have a faulty component, its just because Audi build engines (and the components that make up the engine) to varying tolerances, you have an engine that will not tolerate a remap. Audi do not state anywhere that all their engines will tolerate a remap and produce three hundred and whatever horsepower, they say it will produce 265bhp. It may be the case that the majority can be mapped to 310 bhp without issue, but that doesnt mean that its audis fault if yours doesnt.
You may be able to make that engine tolerate the remap (by fitting replacement injectors, or by using injector cleaner etc), but you shouldnt complain that your audi which produces the factory stated power quite satisfactorarily is somehow defective, when it is operating exactly how the manufacturer said it would.
I say again (just before I get flamed for this opinion), that if your car misfires when totally standard then your car is clearly not performing how audi state it should perform and should be fixed under warranty.
As an aside, and nothing to do with this discussion, anyone who says that software cannot break hardware is not being truthful. I could write a map for my caterham that would melt a piston in short order.
