In general, you want to be careful doing your oiwn work if you never have. You need to know a little about a lot. Like, how the various parts fit together, where the real factory seams are (if you dont know), how to cut without distorting, how to weld without distorting (and BTW, never "quench" or use water on a weld...you are sure to deform all kinds of things that way not to mention introducing water to fresh sheet metal....), and what parts will also need replacing before you start. Then there's finishing the welds (grinding heats almost as fast as welding), and plastic filler isnt the best for seams. Fiberglass or All Metal should be used on weld seams, then typical soft fillers. I dont like to replace more than what's needed. On some cars, thats small areas. On others, your "1/4 replacement" turns into 1/4, wheelhouse, trunk extension, trunk drip rails (not repro'd), filler panel and/or tail panel, and rocker patching.It's not cut and dry, and as you are finding, most shops wont touch it unless you do it at least as well as they can, if not better.
