I went to test drive an Evo that I may be purchasing tomorrow and I have a few questions. While I was test driving it, I noticed that the boost reached approximately 28 PSI. I didn't take it up to redline, but I was told that it tapers to approximately 20psi. Is this unsafe? If so, could I just turn it down to stock levels without getting retuned? The guy at the dealership stated that they reverted the car to the stock tune after removing the downpipe and test pipe. The car has the following mods:

Some type of catback, intake, intercooler pipes, and MBC

After I pick the car up, I plan on logging and getting it retuned with a downpipe and HFC, but I want to ensure that everything is safe in the mean time. Thanks!