Bellies in the line, need to replace it
So I bought a house about a year and half ago under the assumption no work was needed. Never had the pipes inspected because in this town it is required to be done before selling by the seller. Come to find out the prior home owner was shadier than slim shady and stingier than Mr krabs and found a way to get only half of the sewer line inspected before selling. It was the part that went from the house to the road in which he had just replaced with new pvc pipe. However we now know the pipe under the foundation is old terracotta that has many separations and bellies in the line. Due to this it needs replaced and can’t be done via trenchless repair. However my plumber just hit me with an outrageous number of $17k to do roughly 40ft worth of pipe (note I am not asking for any other prices nor am I asking for someone to do this for me). Clearly I’m not gonna go that route and have decided (against my wife’s complaining) I’m going to do this myself. I’ve priced out the tools, roughly most if not all of the materials and it’s less than $1000 for that. I’m looking for any advice before I move forward with this, anything I should know that could make this process easier such as do I really need a 16 inch concrete saw blade or could I go with a cheaper 12 inch and be fine. How should I go about placing the new pipe? I know it’s recommended to have 1/4 inch of fall every foot of pipe. Any advice is appreciated. Also so ai doesn’t flag this as breaking the rules, I live in PA where it is legal to do this myself, so long as I get a permit to do this which I intend to. And after reviewing what could go wrong it seems to be safe with the route I’m going of limiting concrete dust when I cut the concrete slab.