you will probobly have to do the injection kill switch different than me because my jeep is an 88. what i did was put one wire on my map sensor to the wiring harness ground. i do not know how right that is but it worked on my truck, and would not suggest putting anything to ground on a newer vehicle. the only reason i had the guts was considiring the fact that i had a spare computer and a spare map sensor out of a 2.5 cherokee that i scrapped.
as for the alternator the only thing that i did was put a switch on the alternator field wire. if you are not familiar with how an alternator works you can go to
HowStuffWorks - Learn How Everything Works! i have found alot of usefull knowledge there.
the only benefit to the alt not charging is , when the alternator field is turned off the alternator does not charge, therefore eliminating drag on the belt.
i use the injector shut down when i am going down hills and or down shifting to a stop. if you have an auto it will not be much use