Vance & Hines header for KZ1100A-2 (1982 J-model)

Am looking into replacing the stock exhaust, and looking at a V&H megaphone unit made to fit a 1982 KZ1000-J.
If I do get it to fit my application, I'm wondering what surprises await once bolted on?
The stock air-box will (preferably) be retained, though modified to allow more air through.
I'm a daily rider, and do get on it from time to time...most of it, actually.

Any advice?

Anyone there???
The header is to be delivered tomorrow (Mon 5/21)...