I stock most of those models and information on purchasing can be found here
http://forum.bikerscout.net/index.php?showtopic=5875&hl=aker&fromsearch=1
Or email me at familyjim72@yahoo.com
I am not familiar with the 8628 model. Are you sure that is an aker amp model? There are fakes out there but the have half the battery life and the sound quality stinks. You did leave the most popular models off of the list, the aker MR1506 black 10watt voice amp. The other popular amps are the MR1505 12watt (indentical to the MR2100) and the MR2200 16watt amp. Also note that the MR1700, MR2700, and MR2800 have built in MP3 players. They are not very user friendly and they store the music on a SD card or USB drive that both stick out. I have not promoted them for legion use because of that. Also, I have a tubular aker voice amp (AK38) that is 25 watts. It is a beast both in size and volume.