Garage Door Repair

[TX63CONV]

Check me on my plan of attack to repair my garage door:

The attachment point for my garage door motor and spring are a 2x8 lag bolted into the wall. Hard to see from the picture but was originally one piece and has split. The side with the spring bracket is secure--the other side with the garage door motor chain is almost completely detached from wall.

Step 1-remove the lag bolts holding the garage door motor chain to the 2x8
Step 2-remove the bolts holding the spring to the broken 2x8
Step 3-remove the broken 2x8 from the wall
Step 4-install new 2x8--i have a 8' board but not sure I will be able to get the entire board into this space
Step 5-secure 2x8 to wall at studs
Step 6- re-attach spring and motor chain to new 2x8

Questions:
1-The spring worries me and I know can be dangerous; the middle bracket is just a support bracket and as long as i don't open the door, should be fine?
2-Does what I describe seem possible or should I call a professional to remove the spring and then replace the 2x8?
3-If too dangerous/complicated, would you replace just the broken piece on the right--the spring bracket seems solid?

 

[Dumber than lumber]

Even when I was younger, this is not something I would try to do on my own.
Those springs are really wound tight (not inserting joke, but I could).
You can buy a spring-winder device (I have seen them on Amazon and Youtube) that makes the process look safe/r and less intimidating.
Some guys might call you a wuss for not tackling this yourself.
BTW - your sequence of steps does not include anything about removing the spring tension.
Unless you have lots of time and almost no money I would advise you to call around and get it done by a pro. My guess is that a pro would do it for less than $500.