IS250DC

My long-term local mods installer said the Megan's weren't a good choice, quality, spring sag etc. But, this thread sounds like they are a good choice. Did anyone do an upgrade from another coil-over like Bilstein, Tiens, etc that could share a comparison to the Megan's. How long have you guys had these installed? I don't want to drop the back but .50-.75 and the front 1.0 max, will the Megan's accomodate? My ride: IS250 RWD, chromed stock wheels, stock suspension (but shopping). Thanks for the input, anything will help.