The MTM is a tuning box, but appears to be more sophisticated than the competition (DTUK, TMC), as it appears to intercept more than just the 2 boost sensors, and RPM signal. This is probably the reason why it costs much more.is this M-cantronic like the box from DTUK? not actually a map but a plug in tuning box?
http://www.mtm-online.de/en/Audi/S3-8V/2-0-TFSI-221-kW-300hp-Quattro?FZID=S38V221Q&KIT=m2s3300360qm
I am tempted by the TMC box, as it doesn't appear to need a connection to the battery like the DTUK box does.
http://www.tmcmotorsport.com/TuningBoxDetails.aspx?s=2842500
There is a bit of chatter on the R Forum about the TMC box.