This was bought for my old 3800SC L67 GTP. All you will need to do is follow the instructions on the hook up and install the coils. As I never got them from the guy that sold me the set, so you will need to buy longer coil bolts thats it and mount the system.
Just look up MSD DIS4 on the msd site forums and there is a bunch of information there. I would use this on my 2.8 but it does not work with distributor system.
I'm running the msd set up on my car. Despite posts to the contrary, I found a huge difference after installing the FULL kit. Box, coils, adapters. I also installed a new gm base plate as they start to have issues with age. Make sure to purchase compatable wires and plugs(gap .40-.45 as per msd).
The base plate is the oem ignition control(the thing the wire harness attaches to under the coils.) The msd adapters go between this part and the msd coils to independently control timing/ ignition.
I did a full ignition swap(had new wires/plugs but changed them again to match the msd parts and eliminate any potential issues)
I noticed an improved idle, better acceleration, less throttle lag(bogging). As for mileage, I really couldn't say. I have an slight issue when driving my toy. The go pedal only has two positions, On an off.
For part #'s I'd have to check.
Again this is only my opinion but a tech I spoke to at msd runs the same system in his 3.8sc Fiero.
Just a side note, the gm base plate had served duty on a total of 4 motors and was subjected to Canadian winters/salt. As my motor/tranny were new outta the crate, I decided not to change any related parts while dropping in my cars 3rd 3.8. first 2 were higher milage and threw mains. If yours is free of corrosion and clean there should be no reason to change it. It was quite expensive if I remember correctly.