the 450s will burn up the ecu you need the resistor pack that the goes with them. other than that they are close to a 4g63. I think the stock ones are around 280cc but don't quote me on that I just know its in the 200s. check out
www.club3g.com and look at their threads about it many people have boosted those motors and there is a lot of info on that site about doing it.
good luck, I only have about three more parts to gather and I will be doing the same thing.