Hey Mikey,
Definately count me in for the Auto Salon. I have entered my car into 3 different car shows, (ShowOff, AutoSalon and Auto Expo). Auto Salon is by far the best car show to participate in. However the selection process can be very difficult. Last year, when I entered my car, they required a picture and a written profile of the car. I dont think they will allow just a stock FTO in. If you want to have about 5 cars, they all need to look different, and be original in some way. Im only going by last years selection process. It may be different for this year.
The costs involved can be pretty expensive. Off the top of my head, I think it was about $85 to enter a car plus about $35 to hire a power point. A power point is vital if you want to run your sound system on during the event, and other things like spot lights etc. You must also consider things like drop sheets, barriers, lights etc. These things cost money.

You must also ensure that your car is in top shape. Its not worth showing your off your car if it looks average.
You can also go to the extreme of getting promo girls wearing club T-Shirts, giving out stuff to promote the club. (Which equals more money). I did this at the Auto Expo for the Exclusive stand, and it turned out to be a major success.
As for security of your car, the cars get locked up for two nights (Friday and Saturday) So be prepared to have no car for a whole weekend. The cars are pretty safe at night, but during the day while the event is on, it is highly recomended that someone stands next to the cars. There are a lot of dickheads that jump in the car, and play around with things in the car.
Im not writing this to scare anyone, I am just telling you of the experiences I have had in the past. I am warning you to give it a lot of thought before you enter your car. This is the reason why, I want to enter only 1 car show this year. I hope this has helped you guys in some way.
I am also willing to answer any questions about the shows