Has anyone had any experience with DropZone Coilovers? there is a set on eBay right now, they look pretty versatile.

DROPZONE coilovers are precision engineered to be ultimate in suspension performance. Carefully matched springs rates and height adjustability provide exceptional handling, response, control and balance. DROPZONE coilovers allows you to adjust the vehicle's lowering from 0" to 4". All DROPZONE products come with a lifetime warranty. These are not rough or bouncy.. and they do not sag like other coilovers. This is for a complete set of 4, springs, perches, o-rings, and adjustment tool. /shipping is 17.00 anywhere in the 48 states add 1.00 for insurance. Payment Money order/Cashiers Check, Personal check must clear, Paypal. E-mail within 3 days, payment within 7-10 business days.WWW.TechnikConcepts.com

I am looking for some springs in the future, would these be good to lower a street car?