That's the catch...you DO need all that stuff for the ECU to operate correctly, or you *may* find the car won't go beyond 35 mph in 'limp' mode. The car manufacturers have done a pretty swell job of locking us average folks out of the loop when it comes to modifying the ECU's. Everything is integrated, you can't shut off specific areas. Some cars even will even cause problems if you change the braking system, they use the ABS sensors as part of the OBD 2 system.
My WRX, for example, cause a MIL (malfunction indicator light) to go off because I tightened my gas cap to only *one* click, not the prerequisite *two* clicks, which is cause for emissions failure. And besides, in most states, updating an older chassis with a modern driveline means you have to pass the emissions standards for the year of the engine, NOT for the year of the chassis. Heck, in Connecticut last year, some of the car rental companies were using the OBD 2 systems to track and record the speeds cars were traveling at, and were subjecting the renters to fines....thankfully that was thrown out of court.
*Sigh*, time to get my bicycle back out, this new technology is killing me....
Bob