I had both IM50 and IM40 AIO.
Both had aquamaxx 1.5 HOB
Get a titanium heater with a controller (they're shorter than the glass model)
Had the autosmart ATO and Tunze 3517. Both work fine
Flashguards are fugly
Get the xr30 chinese knockoff A8se
If you're on a budget buy used tanks.