I've had nothing but great success from spec. Their drivability/durability is unmatched. I use their 4+ in a 3850lbs awd 630+hp car with literally over a hundred launches, 20k miles and still running strong. For a single plate clutch I won't ever buy anything else. Hence why I have one coming to go with the single I just bought.
2010 e92 M-sport Mods: VM Top mount 6466, Aquamist HSF4 w/custom direct port. VRSF IC + Exhaust
335i 2009 e90 665RWHP Mod's: Vishnu/FFtec 6466 ST RIP
3000GT VR4 1994 647AWHP Mod's: Fully built/forged block, twin TD-05's, Meth, and a whole lot of support.