i recently had my gtp tuned, and the guy at the shop told me i need new spark plug wires, saying something about the numbers he read on the wires are too high and should be around 100-300. is this true? in addition he told me until that happens dont beat on the car, but at about half throttle boosting about 5 pounds the car seems to like jerk/bog is this the belt slipping? or something else?