comments on your spring replacement, the tortion is designed for the weight of the panels(sections). you first need to know why you are losing tention. the door should work easy with a opener on it or without one. this is why it is called tortion spring. The tortion spring is like a shot gun ready to go off, if you unscrew the pins at the end of the springs you better watch out! It will take your arm off, or your head. Call a qualified garage door guy, think about it you are 7' plus in the air on a ladder
with usually know one around. spend the $50.00
on the service call...if you need more information contact me at 818 709-1393, I sell garage doors for a living.