1998 Honda Accord Car not picking up the way it used to

Engine Performance problem
1998 Honda Accord 4 cyl Manual 144757 miles

Ok! I got this used car 3 years ago from a dealership. Three days after I got it, the check engine (orange) light came on. Dealer wanted to charge me $2000 for a catalytic convertor replacement. But my oil change mechanic saw the oxygen sensor wire deliberately pulled apart. He suggested its the oxygen sensor and not the catalytic convertor. I was not ready to spend money on either one of those and car had been running fine with check engine light on for past 3 years until recently when I decided to replace spark plugs on my own. But while changing the plugs by mistake I pulled the pin out of one of the wires. Car pickup and performance became terrible. After suspecting a misfire, I got a new wireset (4 in total) from autozone for $45. They looked cheap but autozone people said its the standard for 4 cylinder engines. Although car is running better than the misfire but its not as good as it used to be before I changed the plugs and wires. Plugs are of fine quality but wires look cheap and dont fit as good as my previous ones. Autozone insists that it is the standard for 4 cylinder cars. What should I do and how much is it gonna cost me to get everything fixed!

All replies appreciated!

Thanks.

Sam.