quick-jack
 

I have a 7000TL and the extensions. Has anyone used this combo?, and if so, how high do you need to get the car so that the jack has enough room to rise before contacting the frame. My understanding is that the jack shouldn't be started with load in the fully retracted position.
Thanks, Efish

I have a 5000TLX and my C8 is lowered 0.75/0/0.5" (front/rear). When you add the thickness of the permanent lift puck (0.5") and the height of the rubber block from QJ, there isn't more than 2" clearance with the QJ in the fully lowered position, probably a bit less.
That said, I haven't noticed any issues with lifting the C8 and I have probably lifted it 40 times or so (track prep, changing brake pads, swapping brake fluid, replacing panels, installing air ducts, etc etc)

People that have used the QJ extension have usually found driving the car up on 4 pieces of 2"x12" boards about 2' long allows the combined unit to lift the car OK without interfering with the QJ.