Extension kit required?

I have 2 8ft garage doors but I don't really need them to open more than 7ft.  Do I really need to spend another 140$ for the 'required' extension kits?   

what would happen if I installed the standard rails without the extensions?   I can't imagine that I would damage the unit if I properly set the lower and upper limits and install a stopper on the rail.

maybe i'm missing something.  Any advice will be much appreciated.

Some manufacturers openers actually will open to 7'6" even though they state they are 7'. You are correct in that you could use the 7' rail and just set the open travel limit accordingly. The only problem I could see is if you ever try to sell your home the buyers (or home inspector) could make a fuss about it before a sale could be completed.

Thanks.  That confirms my thinking.

As well, for the benefit of others, here is the reply from Genie.

...if you only need the door to open 7 feet, you do not need to install the extension kits.  The doors will just open the 7 foot travel and be hanging down in the opening about a foot.  If you don’t have taller vehicles that would cause a problem with that, then there would be no issue.

i think you should contact to  for garage door repair.

But this kit is easy to use.