I posted my experience (or the few bits of it) with the falken st115. Also, price wise, this is the price that I got when I changed my yokohama ad07 15" to my falken st115 14".
I have a QM1 (factory white) coloured rear boot of the ER34 for sale. It comes with the factory spoiler as well. This is not a chop shop item but is still in use. Condition is pristine...