Be careful on choosing a VPI especially from the second hand market :
https://www.whatsbestforum.com/threads/my-vpi-avenger-reference-problems-adventures.30077/#post-6293...
http://vpiforum.com/viewtopic.php?f=12&t=13293
http://vpiforum.com/viewtopic.php?f=12&t=13376
http://vpiforum.com/viewtopic.php?f=12&t=13412
http://vpiforum.com/viewtopic.php?f=12&t=13391
https://www.whatsbestforum.com/threads/my-vpi-avenger-reference-problems-adventures.30077/#post-6293...
http://vpiforum.com/viewtopic.php?f=12&t=13293
http://vpiforum.com/viewtopic.php?f=12&t=13376
http://vpiforum.com/viewtopic.php?f=12&t=13412
http://vpiforum.com/viewtopic.php?f=12&t=13391