First: you CAN'T get the 3.0 up to 4.0 standards naturally aspirated with any mods. There's not replacement for displacement, as they say.
Second, what are your goals? I have a 3.0 and made minor power mods and they help -- but it's not a 4.0, just a slightly better 3.0.
Really, NOBODY can answer that poll question well. If you want the 3.0 to come CLOSE to the stock 4.0, it'll take nitrous and/or a blower most likely...and you'll have more potential maintenance problems and "gotcha's" than you would have with a stock 4.0.
So if your goal is to get to 4.0 performance -- forget it. Get yourself a bigger engine. We've had guys blow, gas, and mod their 3.0's and the results were always disappointing compared to a 4.0 -- even a stock 4.0.