You won;t pick up 100, but I would say from expierience, 20-25, maybe 30hp. Which, if you need pistons anyhow, why not. If it was going from 10:1 15:1, you could expect possibly 100hp, but your at the point of diminishing returns. Q-16, will add another 35-40hp over C-16, once tuned properly. Its expensive, and stinks, but definately makes more power.
Frank