The increased bearing wear comes in as the engine Revs higher and the
centrifugal forces cause the crank to flex in the middle.  Generally
increased past the 4000 rpm mark.  What drivers tend to do (some, many,
most), in an attempt to get to speed quicker, rev the engine past 4000 up to
redline, 5800.

(See:  http://www.geneberg.com/crankshaft.htm)

The chip allows the engine to produce more power below 4000 rpm.  This allows
one to shift sooner because you do not need to keep the engine in the higher
rpm band to accelerate to the same speed.

The power range say will be 2000 to 4000 (you can take it past 4000 RPM)
rather than 3000 to 5000.

On my engine, the rpm range is 1500 rpm to 5000 rpm.  I generally drive it
between 2100 rpm to 4200 rpm with the occasional bursts to 5000 rpm.

Plus the engine runs cooler and the oil is "thicker" because it the engine is
not running on the "edge of leanness."

When you lug an engine it is bad for rod bearings especially due to the
pistons being slammed with early ignition of the fuel mixture as it is
traveling up to and the explosive force is being transmitted down the rod to
the rod bearing and then bad things start happening.

Robert