When I did a custom turbo setup on my 2000 S-10, I used PVC, but it was on the pressure side of the turbo (temporary setup) and it got somewhat pliable on me, and I could smell it when I opened the hood. Plus, it was right in the middle of the engine compartment, not off to the side like it would be for an air intake application.
Anyway, this guy's setup looks like it would be pretty smooth-flowing.
What grade pvc did you use? Doesn't really add up as underhood temps don't get any hotter than hot water temps do in a hot water heater. Boost isn't that much psi either compared to what pvc is rated for....odd. I wonder if you used the thin wall pvc stuff, I don't know what it's rated for, but I know schedule 40 will hold up, and I've used it before and it was fine for years.