If you haven't realized already, year after year police become savvier about performance upgrades. There are cities I won't dare drive in because of cops who are literally out to give tickets to modified vehicles. There have been talks in the California state government to start training law enforcement and create task forces to pull over and inspect cars more carefully for illegal modifications.

If you have an aftermarket boost gauge or fuel computer in plain view a cop will ask you to pop your hood. I was told by an officer the reason he asked me to pop my hood was because of the shiny stainless steel muffler and Wilwood brakes. And, wow, did he ream me for all the modifications he found. From the adjustable cam gear to the blow-off valve venting to the atmosphere. He even gave me a ticket for an adjustable fuel pressure regulator. Boy, was I put through the ringer.

So what's a performance enthusiast to do with law enforcement eyeing our vehicles like a hawk? Well, for myself, I found the best thing to do was to conform. Not that I drive a stock ride but I modify the ride within the legal confines of the law. My 1998 Acura GS-R was my stock daily commuter but I always felt it needed some performance upgrades. However, I was worried about turning the car into a cop magnet like all the other cars I own.

The GS-R was already pretty quick but of course it wasn't quick enough for me. Like many enthusiasts I searched the Web for 50-state legal performance modifications. Fortunately, dozens of aftermarket manufacturers have gone through the rigors of passing emission-testing procedures to make their products legal to use on public highways.

I started with a simple AEM cold-air intake for the GS-R. The 50-state legal intake system is constructed from 2-3/4-inch mandrel-bent lightweight aluminum piping. The AEM CAI system tips the scale at barely two pounds while the stock plastic system comes in at a hefty eight pounds. On the dyno the AEM system performed like a champ, pushing the peak output to 149.6 horsepower. The stock GS-R only generated 144.2 horsepower. The AEM system made an additional 5.4 horsepower.

The next performance modification came by the way of a Skunk2 high-flow exhaust system. Constructed from mandrel-bent stainless steel and features a robotically TIG-welded muffler canister the Skunk system is of the very highest quality. The system produces a fairly deep exhaust note but when equipped with the tailpipe silencer the exhaust note is barely noticeable. On the dyno the exhaust posted big numbers, generating 8.9 more horsepower than the restrictive stock exhaust system. Peak power was pushed to 158.5 horsepower.

We further increased the exhaust flow of the Acura with the addition of a 4-into-1 stainless steel header from DC Sports. Constructed of stainless steel it features mandrel-bent piping for superior flow and robotic-welded CNC flanges. And yes, the header is 50-state legal, complete with CARB EO number and sticker. A straight-bolt on affair, we did find it was much easier to maneuver the header into place after we temporarily removed the clutch slave from the transmission. Within the hour the Integra was back on the dyno pushing the peak output of the GS-R to 163.2 horsepower, an increase of 4.7 peak horsepower.