2006 997 GT3 Cup more horsepower wanted

[Markgt3]

Hi all

I would like to know is there anybody who can remap a 2006 997 GT3 cup car to get more horsepower or is there any other way to get horspower without an engine rebuild

Also i have heard some people have upgraded the engines to 3.8/3.9 and was wondering what the reliability was like when this is done and also what would be the cost to do this

Also what sort of hp gains can i expect with either option