Frank,
I purchased the one piece, it did not slow me down one bit.
I can say that this was the first bass boat I ever owned, and I didn't know anything about jack plates or really even how to drive a bass boat.
The sales guy who was an experienced tournament angler didn't even mention anything about a jackplate and if I needed one, etc. Knowing what I know now I would have purchased one, not that it would make a difference for reducing the "bow rise" or not.
I would have also upgraded my electronics, purchased a ladder, and probably some other things, but I didn't know any better at the time.
A foil does make a difference on my boat, it may or may not on yours, it just depends on what you are trying to accomplish. If it's better top end speed or better rough water performance, a jack plate is most likely the better choice, just my 2 cents.