It's odd that you're having overheat issues. I have a Comet that doesn't have the same problems. What cooler are you using? The only reason they should overheat is if you really have a bad cooler installed!
EDIT: just checked and the Comet has Bracer coolers installed by stock. They aren't particularly good (they do about 260k /s). I'm not sure what other differences the Comet has vs Sabre, but overheating really shouldn't be an issue
The Sabre is an old love of mine, but sadly it's fallen a bit in combat prowess ☹️ I still outfit one after every wipe, but I don't fly it nearly as much as I did in early patches.
Component upgrades don't do much right now, ever since the stat crunch. Changing coolers and powerplants doesn't really impact performance. What weapons are you using?