Replaced TBV , loss in boost?

[Andy]

I recently replaced my turbo bypass valve due to car stalling symptoms. Immediately after the replacement, that was done w/o incident, my boost pressure guage on the dash computer is registering .1 to .2 less. I know the guage is unreliable as an exact boost, but it should be relatively accurate(?). I regularly would see 1.7 and now will rarely see 1.5. Any thoughts? I know the small vacuum(?) line can be a problem. Could I have exacerbated a problem w/ manipulation of this line during r&r? Some posters suggest replacing this w/ a longer line that is routed outside the heatshield on the right side of engine. Good idea if I replace it? Where should I get some new line? Is it standard vacuum line? Thanx in advance, I'm kind of a newbie.
andy