In March I replaced the main 19-year old 93-gallon fuel tank on my 1991 Seafarer 228G with a little help from my 9 year old son. We hired Phil from Alloy Metal Works in Farmingdale, NY 631-694-8163 to fabricate a replacement tank for about $750. After siphoning out most of the gas, I removed and delivered my old gas tank to Phil, and he properly disposed of the same for free. I had purchased online from WEMA, a great sending unit at 30% off the listed price and had Phil install it on my new tank. As for the tank coating, at Phil's recommendation I applied three coats of Zinc Chromate to protect the tank from corrosion and then glued neoprene strips with 3M 5200 Adhesive to the bottom areas where the boat well's tank supports are located.
As for the replacement of the gas lines, the hardest part was the replacement of the fill line, which took me about an hour to complete. What you want to do here is to attach the new fill line to the inlet side of the existing fill line by taking a smaller hose and insert it into both lines and then insert screws in same to prevent them from comming apart. Then you pull the fill lines from the tank area until the new hose is pulled through.
I am considered to be a "handy" type of guy, but I logged about 10 hours on this project from beginning to end and took my time to do it right the first time. If you are handy and don't mind putting in the time to save about $800 in labor, go for it. There are other great posts on this topic within the Grady Repair and Maintenance Forum that I found helpful before I embarked on my tank replacement - check them out for more great advice! Good Luck!