Whoa! If you are talking about the gap in the front of the drivers door, then that's pretty major IMO. One of my buddies did his own cage twice. He put his car up on jack stands and then welded in the cage. He never made sure his car was sitting straight on the jack stands, he just assumed that his concrete foor was level (it never is, it's always pitched in a garage), big mistake. When he was finished with his cage install, he lowered the car to the ground only to find that the passenger rear was sitting about 3/4" higher than the rest of the car . It looked goofy, you could really tell that something was not right. Yup, the concrete floor was not flat (gee, go figure ) If he would of told me what he was doing, then I would have said something (anybody in construction would know this, considering it was also an old cracked floor), but he ended up having to cut up his cage and make a few adjustments. Just a little warning to you folks doing a "do it yourself" cage install, don't trust your floor, make the proper measurements! Remember, your car flexes a bit.
!M!