The subject car is my wife's 2005 ZHP sedan (sadly it is an automatic, but hey, I have my M3). The struts are leaking - no surprise for a car with over 125K miles. The shop that is maintaining the car gave a quote that included factory replacement struts at over $300 each just for the parts.

The car rides about as firmly as my wife would like, so I'm trying to avoid any replacement that is going to be more stiff than stock.

The shop's service advisor told me not to use Bilsteins. He didn't say why and I didn't have time to ask. So I thought about Konis.

Koni STR.T Street Struts are available from Tire Rack and others for about $115 each. They're described as twin-tube, non-adjustable low pressure gas struts.

Koni Sport Struts are also available from Tire Rack for about $197 each. They're described as twin-tube, adjustable low pressure gas struts.

Has anyone had experience putting either of these struts on their ZHP? If so, how does the ride compare to stock? On the adjustables, how does the least stiff setting compare to stock?

Sachs also makes a low pressure gas strut for sport suspension (the ZHP suspension is essentially the Sport Package suspension) for about $90 and a different low pressure gas strut for about $100 that is not listed as being for sport suspension. Are either of these even worth considering?

Thanks for any input on these.