[polaris9898]

I have an 06 jetta tdi. I have increased the tire pressure in my car. The car is out of warranty now and I'm trying to understand a few things.

I was trying to find out if I went to larger intercooler if that would help mpg and the pep the car has? The other thing is changing out the muffler to something that's more high flow. I read elsewhere that adding a fogger (water methanol solution has worked well with the older diesel vws. I read some place that he was able to get 3-4 mpg with the fogger on his 98.