Orlando Car Hire

[screwloose]

Trying to organise car hire for our trip to Orlando. I have used usrentacar.co.uk who do look very good value and have found a Ford Mustang convertible or similar for £378 for two weeks using Alamo.
My question is around the 'or similar'. What else could we expect to end up from Alamo given there are no guarantees over getting a mustang convertible.
Also would you advise pre paying for a lesser car and trying to upgrade on arrival? What normally works out cheaper?
Thanks for any input.

[bint]

We ordered a Sebring convertible from Alamo, arrived in Orlando and got offered an upgrade to a Volvo convertible for about £70 for the 2 weeks we were out there.

Didn't book direct, went through Holiday Autos.