The COPS would be fine, if you pulled the COPS as to get to the plugs, you should inspect the rubber boots and springs, if they are cracked, hard or brittle, go ahead and replace the boots and springs as they are sold at any auto parts store on the cheap. They are sold individually, and each new boot comes with a new spring. So it may be wise to replace all 8 while you are doing this job. I replaced all 8 when I bought my newest stang just for a piece of mind and it would suck to have a boot rip and need a ride to the auto parts store since this was my DD.
2015 Race Red Performance Package GT 5.0 (435hp) stock
Still in the making Updates coming soon!