1994 A4 49,xxx miles. K&N CAI, SLP Foil,no cat, BBK Crank pulley, Hypertech programmer, Trick Flow Inlet. Gonna change my plugs and wires. Anybody got any suggestions? Should I run colder plugs? I live in the panhandle of OK at about 3500 feet above sea level. Thanks in advance.

 

Use a stock heat range plug, platinum or iridium, gapped to the stock 0.050". The NGK TR-55 is good. There is a Rapid-Fire that is OK, but I don't remember the stock platinum part #. Avoid "gimmick" plugs like Split-Fires, multiple electrode Bosch, etc. The stock AC/Delco platinum plugs have been known to lose the little platinum pucks off the electrodes, and when that happens, you end up with a huge gap. When you pull your plugs, if they are still the original ones after 49K miles, it would be interesting to check the gaps, just to see if they have lost the pucks. Lose one puck, and the gap opens up to 0.070-0.075, lose both and they can be at or near 0.100".

Curious why you are interested in a colder plug? Generally, you need to go a step colder when you bump HP up by 75-100HP, or go to a power adder like forced induction or nitrous. Running at 3,500-ft, you're already down on HP, and shouldn't need anything colder than a stock plug.