Welcome. The car looks great. As far as sneaking the springs in...the racing beat springs are as mild as it gets. Slightly stiffer, slightly lower. She might not even notice.
Oh, and the first two pics aren't showing up for me.
I don't know... I did a full custom exhaust and a short ram intake and gained 11WHP and 13WTQ... thats a ~15% increase over stock... Call me crazy but i'd say that's 'worth it' on an N/A car... for less than $1000