Increasing spark intensity will give me more HP and or MPG? Thanks.

 

In theory the more complete your combustion the more energy will be produced and an increase in HP and or MPG if you can keep your foot out of the gas.

 

Today's stock ignitions are about as hot as they come. Most have the coil directly on the plug and don't use plug wires anymore.
Just using a quality spark plug and changing them as recommended is the key to being efficient.

 

Not enough to measure.

 

Not enough to justify $425+ for a set of MSD coils. maybe if you were cammed, heads ported and a blower/turbo.

 

Still not enough for MDS coils either.

if there was a way to come up with better fuel usage by now someone would have found it IMO.

You could get custom tuned and de-power the truck to get better MPG IMO though.