bose upgrade?

You don't need the HU, as the Bose system uses exactly the same unit.
If you're thinking of performing an upgrade from non-Bose, then it's seriously not worth it, you'd be far better keeping the stock HU and going aftermarket for speakers and amp.
The amount of rewiring needed to reftrofit Bose will actually be more than going aftermarket as you'll need both a power loom for the amps, and new speaker loom as all the speakers are amped whereas non Bose runs the fronts off the HU. Yes it does sound better than non Bose, but it's not that big an improvement. If I was going to all that effort I'd want a dramatic improvement, which you can get with aftermarket.