hi greysude, if your not after the genuine floor pan shape,flat steel has work fine for me-as mine doesn't have the above problem's.providing you weld thoroughly to the appropriate rail's,inner sill,underfloor support brace,and of course all the way around the piece you are fitting.as i have done this as well as fitted the hadfield floor hump in my fe and is fine in strength-and doesn't pop up etc,p.s-weld all the level bit's first then hit the new metal into the original crease's of the floor pan with ball pain hammer and weld the rest.hope it help's it come's up fairly neat too if you understand my LINGO.COL58FE.