you can install the plugs further inside the the tailpipes than the recommended 4-8".. but the whole purpose behind it bein 4-8" is to guarantee that Oxygen is present.... you could install then further up the pipe, but you may need to drill a hole n weld in a lil short stubby pipe of tube maybe 5mm or 10mm dia and position it toward the front of the vehicle so as you move air is forced into the tube,therefore supplying you with the all vital Oxygen.. also remember to keep the plugs away from your muffler, and Never ,repeat NEVER install the plugs infront of a Cat or muffler....not unless you wanna frickin big bang,or a guaranteed way of destroyin the cat... also if you use theose weenie lil sparkplugs from chainsaws/lawn mowers etc..theyll be less obtrusive.....
