Kenne Belle Build

I have an auto 03 GT with 150k+ miles on it. I'm wanting to add a Kenne Belle 2.1L blower on it, likely running around 9psi. Now I know KB advertises that this particular blower can be installed on a stock engine and add 105HP (or whatever they say) but I'd like to hear it from you experienced gentleman. With my car having the miles on it, what would say definitely needs replacing before adding something such as a blower?

Oh I know how you know lol. I went through and read your whole build thread, can't have good luck to save your life haha. I've read reviews and have heard from many people that KB is a good company with quality products. Reading in the 2.1 I'm looking at it looks pretty straightforward, largely just bolts on and replaces the intake manifold. I of course understand that few things rarely are that easy. I am quite sure I need to replace my valve stem seals as I slowly lose oil over a few weeks and my car smokes black after idling for several minutes. Can the stock internals handle 400hp? I plan on replacing all of the intake components and adding a BBK o/r x pipe. Already have Borla stingers. It should be noted that the KB is a kit and comes with everything they recommend your car have and if you choose to go up from 6 to 9psi they give you the recommended options for that as well.

Yea I've been needing to replace the seals, just haven't had the time. The KB comes with 36# injectors and boost a pump. You have the option of getting it at 6psi and non-intercooled. This car is a daily driver, so I'm just wanting a little more power to play with. So if I could get by with 6psi for a while to get bump me up to 360sh and eventually graduate to more boost, I'd be cool with that and after the intake and exhaust upgrades I plan on doing, it could get me clear to 375.