I spent a lot of time in Maui. Last few times i rented a car from a great place, a convertible mercedes at a good price. this is thier site: http://www.rentacarinmaui.com/
they were very accomodating the first week when they didnt have a bmw they upgraded me to a sporty mercedes. Last trip i just rented it to start with.
Tyree was the man
even though thier office is near the airport he met me for a exchange 20 miles south and if prearanged would probably meet you at the pier.
Dont go to Hana, it takes all day and is a headache to drive and theres nothing much there.
we went by helicopter and took a limo van back. It's a tour called the hana skytrek and it made me glad i wasnt driving.
good driving is on the leeward (dry side) from Kahana up north, down the coast to Lahaina's touristy places, east on honoapiilani highway to maalaea which has an aquarium and a small boat harbor..then go south to Kehei (my favorite) and if you keep going south you wind up driving past huge cactus and into a lava field near la parrouse bay(sp?), it looks like the surface of mars out there. Maui has 11 out of 12 climate zones in the world. you can go from sea level to 10000 ft at the top of haleakala (another alien landscape worth a view).
to see what happened to the hippies go to paia town, in the hills, lots of art and stuff, willy nelson owns a bar there, cool place.