There will no crashes/errors if you'll follow the steps correctly. For which model i'll say go with 2100 series or the early 2500 ones that are below 3.56 as mentioned above, but honestly focus on getting one that is in good shape which is the most important thing IMO.Since I'm a newbie which ps3 slim model is easiest to cfw without any errors and crashes also does it need to has a specific system software ver?