I know this has been discussed before, but I wanted to provide some personal feedback about the map I have just loaded onto my A6. It's a 1.9tdi 130 AWX avant with nearly 200k and is my daily, family car doing approx. 40 miles a day. I researched remap and tuning box options to improve the power and MPG, and after reading many positive reports on all the forums I decided to go DIY and went to Blacksmoke to buy my map.
I purchased an MPPS cable on eBay (I appreciate this is not genuine but worked fine for me) for just under £30, read my ECU and sent that file to Andrew at Blacksmoke. He sent back the modified file including EGR delete the next day for £45 which I then installed on my car. The process was hampered by issues with my laptop (the old software has to use XP) but Andrew was on hand at all times to provide support and advice. The upload was exactly as explained on his site but was quite a nerve racking couple of minutes...!
The difference in feel is very impressive - much smoother power delivery and a substantial increase in torque all the way through the rev range. It feels like a bigger capacity engine! I haven't had it on a rolling road yet to verify, but my understanding is that it should now be running 162bhp and approx 280lb/ft. It doesn't feel spiky, there have been no warnings lights or funny noises so I'm a very happy customer!
I appreciate that there is a risk with DIY, and that the Blacksmoke maps are not "optimal" or fully customised to my engine. Having said that I'm not trying to achieve 250bhp with a selection of other upgrades, and due to the mileage I don't want to be pushing it too hard anyway. It also cost me just £75 all in, and although I haven't run up substantial miles yet to check, even an increase of 5% MPG would be paid for in 6 months during my normal driving.
I'm not affiliated with them in any way, I just wanted to share my experience to encourage others to look into it as an option.