They do stiffen the car, which may or may not make it more durable. I haven't had a good chance to really test these bad boys out yet. I'm taking a trip to the mountains this weekend (Mad River, Sugarbush ski area) to give them a good work out.

1999 Contour SVT #1966/2760, Silver Frost/Midnight Blue Koni Kit, Mille Miglia MM-S rims, B&M shifter, Stazi mesh, SFCs, optimized Y-pipe & TB, SS break lines, K&N drop-in, Infinity Kappa speakers, MTX amp/sub