SM4 has cheapo resistors used to cut voltage to injectors
 

Mine have resistance of 5.6 ohm, injectors - 2.1 ohm, ratio is
8 : 3, when max 12.9v flows through both, # of watts wasted as
heat is 12.9² ÷ ( 5.6 + 2.1 ) x 8 ÷11 = 15.71w.
http://www.autozone.com/servlet/UiBr...3d800cf24b.jsp
A buck*converter ( costlier but far more efficient )
http://en.wikipedia.org/wiki/Buck_converter should have been
used instead ( as used on pc's mboard, for cpu ). Tandy's 1984
catalogue already had 2 * ( part # 14-844 & 270-1560 ) for sale
.. If fitted with ECU in boot, a * will not get too much heat, i.e.
will last long ( like those on mboards ).
Battery & spark plugs will get more amperes : easier start, less
sulfation of battery ( from higher charge ), less exhaust noise (
from bigger sparks ), more torque & mpg.

SM4's short 4-1 exhaust manifold & steel wheels are cheapos
too.