Cylinder Head Guru's, can anyone help?

I have a set of GT40P's on my car currently. They are just as they were when they came out of the box. I am thinking of doing some more modding to my car and want to get some head work done. My question is, how big can I have The valves cut to on the GT40p's? I would like to get 2.02 intake and somewhat bigger exhaust also. Is this overkill? will I have any piston to valve clearance issues? Can the heads even be cut that big?

Also, maybe i'm heading the wrong way, are the stock vavles on these heads suffecient for my current combo?

Thanks!

cool, thanks for the help guyz, found a lot of really good sites on what not and what to do with the "P" heads.

Thanks!