Whenever you want/need a new engine and pipe, you will need deeper pockets, but the rest of the time I have found that sedans can be more expensive. I know that tires are for sure at my track. I would go through 2 sets of tires a Sunday with my sedan, where as 1/8 scale can get 2 Sundays out of a set..... Plus there's nothing like going through a sweeper at the end of a back straight with out lifting and hearing the engine load up verses having to lift with a sedan (unless you want to 'kit' your sedan).......
So just go out and run it! If you are a little slow at first, who cares, everyone had to start sometime. Good Luck!