I have a 1988 325iC with about 168,000 miles on the clock. Runs pretty good with a GIAC chip I got from DynoSpot Racing in San Jose. But always looking for more low-end power. I was on the Bosch site and see they have several different plugs to choose from. 4478 PLATINUM+4 Do not gap. Gap is not adjustable. 4306 PLATINUM+2 Do not gap. Gap is not adjustable. 4506 PLATINUM IR FUSION Do not gap. Gap is not adjustable. 6234 PLATINUM GAP=0.028" 4034 PLATINUM PLUS GAP=0.028" 7509 SUPER GAP=0.028" 7909 SUPER PLUS GAP=0.028" I use the standard 7909 Super Plus. Has anyone run the Platinum plugs? How do these other products affect performance, economy, etc? Thanks.