I have just installed Rein boots on my boxster... but the half-shafts are not as yet installed on the car, so my experience is limited
I have been running non Porsche boots on my 928 for several years (same part number) with no problems... but not a lot of miles and I don't remember what brand they are.
928srus, a very reputable 928 parts supplier, sells a kit with 1 boot, clips, grease and flange for $11.95, no manufacturer name mentioned but it sure ain't Porsche at that price.