The adjustability is nice, but for performance purposes some would say springs are actually better, and they're like 1/2 the cost. Plus your car comes with non-adjustable springs to begin with.
I'm not saying there's anything wrong with coils, but i dont see why you wouldn't recommend springs.
I run a canadian HID kit company, if you have any questions about hid kits in canada or would like to check out our products please contact me here: http://absolutehid.ca
Hot: 2001 Estoril M Roadster
ZCP 19's michelin supersports, ZHP knob, JL 8W3
Cold: 2002 TiAg M3 6mt ZCP 19's michelin supersports, deoranged, dechromed, led tails, ZHP knob, UUC SS v3, GROM, OEM 18's w310's,
fun: 2006 YZF-R6, black