Is it worth it to upgrade my iphone baseband?

I have a iPhone 3GS and its running modem firmware 05.16.02. Is it worth upgrading to the iPad baseband so I can unlock it with ultrasn0w? I realize I wont be able to downgrade again, and i wouldnt be able to send it to apple for repairs. It doesn't have a warranty anyway because my friend found it on the side of the road. I don't really want to lose my GPS while upgrading, so I'm unsure about it. maybe there's another way to unlock it without upgrading or costing me any money? Would it be worth it?