I am confused at what you are wanting to do..
Do you want to upgrade to the stronger 8.8?
If so don't even mess with disassembling yours, 8.8's are a dime a dozen.
You will need a 94 or 95 model year 8.8 from a mustang, because this will come with the disk brakes and the correct length.
If you're patient and check your local salvage yard and craigslist you can snatch one up for $100-$300.
Actually, if the OP wants to swap in an 8.8 into his 95, any year 8.8 housing from an 86-98 Mustang will work.
8.8 housings from 86-98 are the same length. The axle shafts and brakes and brackets and moan braces from the 7.5 can be used. You can take the hard brake line off the 7.5 and use it with the 8.8 or make new lines.
As clark98gt said, it will keep the same width.
If you want to go wider (have the effects of using a small wheel spacer), then get a complete 8.8 (with axles) from a 99-04 Mustang GT as they are roughly 3/4 inch longer (per side) than the 94-98 setups.