u cant avoid rust, its inevitable unless ur car is made of plastic....
BUT ITS NOT!

.......

....my 93 v-6 is still iin very good shape (as far as rust wear and tear goes ) with 220000 on the body and 3400 on the engine....the only rust i really have is the y-pipe which is perfectly normal and a bunch dents i have in the car, they are not problematic though and not rust would even be evident if the dents and otehr damage werent ther. No rust on the underside is noticeable as well except in expected parts.