An AFC would be the cost effective solution. To "chip" the ECU you would have to send it off to someone who can tune those. A good ROM tune will cost you $500. I was looking for RB MAF's for you and the RB MAF is a J60 MAF. I am pretty sure about that. You could try an N60 MAF without tuning it. It may work, but I am not for sure. But you would definately need something to tune with if you use an N62. Good Luck.

Ohh and you won't see a big difference right away. You will just have the Potential for more power. More Air + More Fuel = More Power. You can use the bigger MAF along with bigger injectors and a tune and turn the boost up and make more power.