We do have a bike rack that will work with your daughter's 2004 Mazda.
I recommend the Hollywood Racks Over-The-Top Bike Carrier, part # HRF2. This bike rack is designed for vehicles that have a spoiler like the one on your daughter's RX-8. The high-rise frame extends up and over the spoiler and the carrier folds down for easy storage when not in use. This carrier has a weight capacity of 35 lbs per bike.
When carrying bikes with alternative frames like kids bikes or women's bikes I... view full answer...
Inno test fit their roof rack part numbers # INXB123-2, # INXS250, and # INK163 on a 2008 Mazda RX-8 just like yours and they determined it fit well. While we haven't had the chance to test the fit we can guarantee it will fit your vehicle and work great!
I attached a link to this page for our return policy but you wouldn't need to worry. view full answer...