I will add that for the Silver class any of the world models 46 size warbirds will break out with a YS115 on 20% nitro.
For Gold I have ran the WM mustang and with 60% nitro on the 13.5x13.5 APC prop it runs right at the 1:25-1:26 range and can easily run 1:30. I have ran a best of 1:25.6 and Chip Hyde has ran right at 1:25.4 with his.

I know a lot of people have the larger 60 size top flight kits and kits from Hanger Nine and with the DLE 20s these are perfect for the Bronze class. Fly these same planes with the YS 115WS and some 30-35% nitro and they will run Silver speeds.
For the WM spitfire I have run as fast as 1:19 with it at Sacramento. The WM spitfire I think is the perfect plane as it can fly in all three classes. I have one for bronze, silver and gold.

Side not I have been flying planes since 1979 and never thought about competing but I started this warbird racing three years ago and man I have to tell you it is the most fun I have had flying rc planes. Also You just cant beat the sound of the YS with open header on some 20-60% nitro.

If you are kinda bored with your normal routing of flying you should really give this a try. If you have any question hit me up here on the forums or at my email.