im sure theres been a post on this before??
anyway i had one on my last car saxo vtr and it was ok picked up on the flat spots and helped slightly through the gears - but it was a saxo which anything would of helped to be fair i think for a 1.8 or above wouldnt bother you wont notice anything at all but if you go to this page you will have all the gumf http://www.ecotekvalve.co.uk/?gclid=CKyY56fWpowCFQrlQgodAWebMw