My antenna is 12" and not flexible at all...and like Project03 said I don't find a difference in the reception at all either...and man does it ever look but that that stock flying whip or an antenna I freakin' hated that antenna soooo much flapping in the wind like it had a mind of it's own it got so bad I took it off until the new one arrived a week later.
I got mine out of a local dealer...I don't know the supplier I thought it was AVS but not that sure...Car washes dunno my sorie has only seen my wash mit...I never go to a cash wash but I would assume it would as it's really stiff.
I purchased mine from AntennaX.com. Here is a link: Click Here.
I wanted to keep the stock look, so I opted for the 15" OEM Whip Replacement Mast. Looks just like the mamouth stock one, but a hell of a lot shorter. They got the Euro-style rubber one, also. Very affordable mod... haven't had reception problems, myself. They included a bunch of adapters with my antenna... so you can test-fit to see which one looks the best from your Sorento to the new antenna. Hope this helps.