Portamigs are pro quality British hand built to order machines, considering this the price is very competitive, compared with the likes of Clarke welders (which weldequip also sells) which are a good diy make, but won't have the service back up of the Portamig long term.
Its like everything you pays your money and takes your choice.
Contact "weldequip" let him know what your going to weld and ask for prices, he can sometimes take a while to answer if his busy or on a long weekend away but you will get an answer.
What part of the chassis needs welding? It’s not the best place to start to learn welding as it is structural and can be subjected to allot of abuse especially if it is the rear cross member. You may be better to pay someone to do the work and have it done properly.
Hi, I have always managed with my oil cooled Oxford welder and just welded up the chassis in the same place. The advantage of using an arc welder against the mig is that you can beld over the end of the rod to weld in tight areas like the area between the rear body and the chassis without having to remove it. Mig of course is much easier depends on where you have to get,