What do I get for my boyfriends 17th Birthday?

He and I have been together for 10, almost 11 months now. I keep asking him what he wants and he wont give me a straight answer. He keeps saying if you get me something for my car, i'll be happy. He has a silver 4-door jeep sahara, 2007. He has a lift, subs, pipes, all that stuff. And I can't find anything else to get him. He mentioned the grab handles as a gift, because his has none. The reason he wants them is so I can get in it better without help. I have got him cologne, a visor, trailer hitch and little things as previous gifts. But I have no clue what to get for his birthday, any suggestions or help is greatly appreciated! Thanks(: