Can you

[JCH]

What do you need to do to make a normal car to a rally car?
Can you use any 4 seated car as a rally car?
And what is the ideal first time rally car?

[Mark]

The minimum would be roll cage I guess. But it depends at what level you want to compete. Even WRC cars are notionally converted from ordinary cars.

[MrJan]

There's a thread already about a good starting point, think most people say that a Peugeot 205 is a good way to get into the sport. In theory you can convert any car, but obviously there are a number of strict rules set out in the Motor Sports Association yearbook that you have to comply with. You also have to consider classes and how well a vehicle will actually perform. For example a 3l Lexus is going to be too big and heavy to compete with the cars that it's likely to be pitted against. Also depends on the type of rallying, for example I've seen Aston Martins on tarmac events but they'd be useless in the forests. Also cars don't need to be 4-seaters, see Darriens or a lot of the Group B cars.

[driveace]

Get the RAC bluebook,and read it for what is needed regarding fireproofing,roll cages etc.Lots of small inexpensive cars with which to start rallying with ,Peugeot 205,Micra,Vauxhall Nova etc