I agree with what people said about deciding what you want to do with your car/engine, and then pick a cam.
But, I'll go ahead and answer the original question... I have never used an X cam, but I had a E303 with 1.7 roller rockers in a '94 cobra motor. The heads were stock '94 cobra cast iron GT40's. It had an explorer intake, headers, offroad H, flows, 65mm TB, 73mm MAF.
The cam made good power up to 6000. It did lose a little low end compared to a stock cam, but nothing you would care about unless you had 2.73 gears still. It had a very noticable idle. I don't know if it would make it through emissions, the rough idle suggested it might not.
I thought it was a good cam, but it was the only cam I've ever put in a 5.0 so I can't compare it to anything.
Jeff