The Lone Star site will be a lot of help but as to the modifications, once you buy the kit you can modify it any way you want so long as it is legal in your state. Many of the modifications come from people who are going to race theirs pretty hard and prefer different things than is included in the kit. Many people just like a personal touch to their cars and modify some things. The guys on the Lone Star site should be able to tell you about anything you may want to know.
Ron