The vacuum pod on my jake interfered with the firewall when I put my II sps66 on. Everytime the engine started or shut down, you could hear the vacuum pod smacking the firewall. I ended up taking the dash apart to esure that their was adequate clearance, and then dented the firewall a little to allow for clearance. All is well now! I also have the magnaflow 5" exhaust too... not sure if that matters or not.