Hmm, looks good! but that's a pretty big dent. I'd be contacting schmiedmann to see what they can do. I don't know about putting sealants around the headers...I would have thought the gasket would suffice? You could replace the gasket if your OEM one looks worn.
Evolve CSL airbox w/Alpha-N tune | KW v2 | Vorshlag Camber Plates | WORK Equip 18x10/12 | Dixis Ti exhaust