My 2012 CRD has always had high egts, around 480-580c (probe within 50mm of turbo out) on hwy unloaded. 106,000kms. Had new injectors and rail recently replaced under warranty and made little difference to egts. 33" tyres and chip installed. Chip probably added 10% to egts. I would like to get my egts lower. How much of a drop can I expect from going stock (less centre muffler) to a 3" system?