factory, the intake is much more restricted than the exhaust side of the engine. particularly when you upgrade exhaust and not intake manifold. So, this is why you'll see more gains with more of an intake cam than exhaust. I'm going from stg II's to stg III intake stg II exhaust. I wouldn't just put in one, the stg II exhaust cam is better than oem. look at the numbers. If you want, you can put in the intake cam first, dyno it, then put in the exhaust and dyno again. I can swap out cams in about 20 mins now after doin it a couple times. I'd be interested to see the results, but I'd bet you get gains. Stg II's are great, I'm looking for 200whp or I wouldn't go with the III at all. good luck, keep us posted.
yo, if you can find the mcnews automotive thread for when they did an involved dyno test of the FR head, you can find the perfect combo (which is mismatched by teh way). You want your exhaust to have a total/maximum flow of roughly 74 % (optimum figure) of your intake flow. I've heard that stage three both sides, or stage 2 both sides for that matter, the ratio is something like 90%...not a good thing for various reasons. Stg III intake/stg II exhaust...but shop brands to get the kind of power curve you're looking for. Some are peakier, some keep the broad torque curve of hte stock engine.