Please help me!! Bday gift question...?

So my dad's bday is on the 28th. He loves cars and electronics. So he was dying 4 this GPS: Tomtom Go 740 Live. Me and stepmom was planning 2 buy it 4 him, but he bought it!! So now I dont have nothing 2 give him. I want a very nice gift! Cuz he has done so much 4 me. So any ideas? He is in his 30's.