FWIW PCA Club Racing rulebook recommends either metal or rubber with aluminum supports. I've used metal stems on my track car ever since I had a rubber stem fail (despite the aluminum support). If you track your car you should use gasketed metal caps whichever stem you choose. I wouldn't worry about valve stems on a street-only car.

If you choose metal stems, look for some alum ones. Some race supply places have them. I'm not sure about ones I see regularly on eekBay.

Thanks for posting the part number. Had leaking metal stems.on the front 7x16 but stem supports with rubber stems on the rear 8x16 - worked perfectly. Just ordered the stem supports.