Yes, it should be installed and re-tuned if you are going to change from a 2.5 bar to a 3 bar MAP sensor. But, if by adding 20% more boost there will be no harm done, why not? I upgraded my turbo and nozzles and the nozzles were quite smoky w/o being re-tuned. Adding 3.6 PSI of boost in my case was a really good idea; I have better power and almost no smoke right now. I still have 2.4 PSI of room left in my turbo, and when my tuner gets his flash tool back, hopefully I will be next to use it.