So hubby's volvo is still getting the P0303 mis fire from the scanner, he has already changed the 5 spark plugs, what's next to change? the coil packs?

he ordered this one, but he told me it didn't fit?!

 

I just looked back at your previous thread regarding the misfire. I should have suggested to you to FIRST try swapping the #3 coil (suspect) with one from another (good) cylinder. Then reset the code and see if the misfire is still on #3 or moved to the other cylinder. If the misfire is on the other cylinder, replace the bad coil. If the misfire stays at #3, then it wasn't the coil. That's basic troubleshooting 101, and I don't know why I didn't tell you that from the get-go.