100 S4 / C4 Servicing Question

hi all unfortuantly i having been having some problems with my 92' 100 S4 ... all sorted now , but i am not happy about the garage who did the work , i think they have been taking the coloured water !!! i'm looking for a bit of advise on the time it would take to complete the following : 1. remove & refit inlet manifold , replace gasket ( one of my water pipe split ) , refill & pressure test system. 2. Remove Gearbox & Exhaust , fit new mass fly wheel & rebuild... the good out of this was my exhaust was poorly , 1 of the cat's had disintegrated ... but it so happened i had purchased a powerflow exhaust from ebay a couple of weeks before .... it fits a treat , looks the dogs & sounds awsome !!!! any help , pointers would be great ...