I'm pretty much a newb at welding, but in time I'm sure I can come up with something decent. As far as a manifold you better go with a tig and know how to weld!!!!!!

My welder will be for exhaust and stich welding chassis for now

 

o i didnt look up the model numbers for yalls machines. i thought they were small 100 amp tig/arc machines. 75/25 is right for mig carbon steel. i guess you already have the valve and hose to go from the bottle to the machine. if not, they can be pricey, thats why i dont have one. if your just doing exhausts, i wouldnt even mess with gas. as long as you use fluxcore and dont mind so much spatter, its fine. if your getting good and are doing things people will see gas would be nice. arcet would be the best place to go for gas, and richman steel off jefferson for steel. or get a job as a sheet metal mechanic as a part time welder like me and all your steel and welds are free..