mustang302:
No personal experience but WMS has been around for a long while and they offer well-engineered parts, imo. When the '05 came out, WMS brought out a 'straight shot' cold air intake that helped pick up the power a good bit. MM&FF or 5.0 did a write-up, too, and you can see from their pictures that the CAI kit was well thought out.
Have you looked at their site, wmsracing.com? Plenty of good stuff there!
HTH,
Chris