I had read a posting about easy E30 performance upgrades a couple of months ago but can't find it now! Anyway, thanks to the guy that posted it. Ive got a 1987 325e and got the model E30-A1 Signature Motoring heat shield and the K&N filter for about $140 total (signaturemotoring.com) The power increase is fu%^king awesome and the sound is not any louder except and high RPMs where it howls! Very cool. Whole setup installed in about hour and a half (but I've got two left hands and take a cold beer after every half hour working).