I can keep up with STi's, stock and with cat-backs. I know this because I have done it with my uppipe, turboback with high-flow cat, IC hoses, and cobb reflash.
krazyimports has the headers/uppipe, catless tbe, intake,pulley, and a utec tuned by Junior.
I believe it is perfectly possible to get the jump at the go, and keep the lead.
Its all down to the driver, and anything can happen on the street