I have tried without success to find an HD gas strut, especially needed for the front. KYB only makes their low line GR-2 for this car, which is fine if you like a Buick ride, not for me. Haven't checked out the RT sedan if that would be any help. Anyone know if the unit from the FWD 300 will fit? It's a 15 - 20% heavier car, which is about the increase of firmness I am seeking.