The EGR affects idle and overall performance. Most of the time in 4 cylinder trucks it's been rendered inoperable due to carbon coking the system up, so it would be fair to say the V6's won't escape similar issues. The ECU will do it's best to compensate for whatever running conditions the engine is experiencing but if you can do something to aid O2 readings, it's worth doing - as long as you aren't restricted by EPA regulations...