As long as you don't overdue it, porting always helps. That is part of what helps the SVT run so good. The extrude honing process is essentually a method for a mild port and polish to the intake manifold and in the case of the SVT to the intake ports as well. The 98 only does the secondary port of the head while the 99 and 00 does both intake ports.
I have ported several heads in my life, none recently. It has always made a significant difference. If I ever decide to do significant modifications to my engine, the heads will be ported.
