I had a caska unit in my mk5 gti. Worked well for me. The interface was a bit crap but it does what it's supposed to do. Never had any issues with it.
Current: 2012 Golf 6R Stage 2, TMSS downpipe, Evoms
Ex: 2006 Mk5 GTI Stage2+, Autotech HPFP, Evoms, DP, R8 coil packs, RS4 fpv, S3 cooler