^sounds like you have a good reputable shop.... and you seem pretty much all set...

and to answer your question... what you run in the 1/4 maters only to how good your tuner is and what parts you end up going with and how your car is running that day and the temperature at the track that day...

see how we can't assess on the internet what your time will be (roughly).

as for the intake manifold ... the skunk2 manifold should work just fine for you but even a stock GSR manifold will be ok... until you start building beyond what you are now... then there is really no need for the manifold to be upgraded just yet