Urban, I don't know your financial situation... and it ultimately comes back to what you can afford.
That said, I would try and avoid the flexible tubing your describing, if at all possible.
The whole dual exhaust set-up on my 46 was done for under $250.00, including the splitting of the manifold, glass packs, all pipe, hangers, and the labor.
You might save a little bit of money going the flexible route.
However, I can tell you based upon the 47 F*rd I'm storing for a buddy, it don't take much at all to bend it, or bust it loose. Once bent, it don't go back.
We quickly and quite easily trashed his entire exhaust system trying to load and unload it from the trailer we used to transport it to my house.
I'm betting my steel exhaust system would have taken the hit and perhaps gotten a small dent at most in the same situation.
