Pinging or knocking in 2000 GT 4.6L

[SoulKeeper]

Hello. I have a 2000 GT Mustang 4.6L. I bought the car with the following mods: Chrome Air Induction w/ K&N Air Filter, Flowmasters, 70MM T.B. I have replaced the Flowmasters with Spin Tech Mufflers, pullies, H-Pipe. Just a few days ago I noticed the car starting to ping or knock when I give it gas around 1500 to 2000 RPMS then is a steady noise when I punch it. I use 94 octane from Sonoco or Exxon gas. Always have. I changed the oil today and drove it around and the pinging or knocking was stil there. I opened the hood and up by the T.B. you can give the car gas by the throttle body. I did that and can feel the pinging or knocking when I give the car gas. I do race the car just like every other Mustang owner does. Any help would be greatly appricated in dealing with this noise my car has now aquired. Thank you.