I'm a pretty good shade tree mechanic, and I can't tell you how many times I've had neighbors, relatives and friends call and ask for help after they've tried some auto repair that was over their capability.
With the questions you are asking, I agree that you are better off going to a shop and paying the price....it's a once in a 150k expense. A shop can replace the plugs, check to see if you need wires, get the correct wires, etc etc etc etc.
I once had a neighbor who had his ford range towed into the dealership because he stripped the threads on the oil filter plate....he was trying to change the oil for the first time in his life....he had watched a you tube video.
Would you teach your kids how to drive by letting them watch videos and then turning them loose with your car?????
There is nothing wrong with knowing your limitations.....otherwise the cost of repairs to fix your mistakes could outweigh the cost of spark plugs....check out the cost of repairing a stripped spark plug hole as a simple example.
Not being mean here, just trying to save you a bunch of money and great burn.......
