I have 9.18.28.610238 and 9.19.1.483935 installed in same device. They work ok together, even using share map/poi/voice to save space. What I can tell you, Avic is much better. Much faster load up time and online TMC works flawlessly. I did not have to do anything special in installation (the sys.txt already have the correct different folder needed) Look in the Avic thread for proggy to change name and icon.