i love the Dubach pipe,and between it,the rejetting,the K&N pro air system w/flange,and drilling the air box i regained alot of power,id say everything i lost from the big foot kit,and then some
the rejetting was kind of a pain,,,,i think i had the carb off,and on about 8 times total which intails tank removal,and to be honost it was irritating
i think i used 6 plugs when trying to get the mixture right,and ended up with 10 uni vents in the airbox lid
if you want more power,these mods will deliver it,,,its the best way to get more ponys,without getting into the internals of the engine,,,,myself,im saving the 686 kit for when i need ie. when it starts getting tired,using oil,burning oil,ect
im not a big fan of going into a perfectly fine running motor to get horsepower,i'd rather wait until it actually needs to be workred on
same thing with my truck,,,,i have a 2004 F-250,i gained better horse power,while at the same time getting more mpg by simply installing a Gibson Catback exaust system,and a K&N Cold Air Intake