As most of the people above have said theres no need for a special head gasket as a VAG one will do exactly what it says on the tin.
As for the cylinder head porting work your after, do a yell.com search in your area for engineers. I did one in my area and it came up with a load of tuning places I never knew were there.
The big companies charge a lot of money for head work and a lot of the smaller places have the machines and know how to do it far cheaper.