Help!!!! Is This Good Deal?

It's a good price and probably worth the effort to change if you intend to change the front to large bolt pattern . Maybe you did that already, dunno.
The drive shaft difference and U-bolt difference has been mentioned. I'll add mention of speedometer gear ratio change and you would need 2 spare tires if this is your daily commuter car.
I bought the same 8.25 rear not long ago. When it's all done I'll have about 300 in it.