Lemme help a bit..
wire is wire, depending on if you keep 'classes' of wire together.. Meaning.. You can't compare solid wire with no flex to 2000+ strand wire (for the same current carrying capacity) flex.. isn't reasonable.. that's like trying to compare apples and oranges.. they are both friut, but not the same kind.. Oranges and Grapefruit, now that's a better comparison, right?
As far as Oxygen free copper.. The only time you 'truely' gain serious benifit from buying 'oxy free' copper is if the wire is SEALED.. Not just in the insulation, but tinned.. If it's not tinned, you can STILL get oxygen to touch the copper and cause oxidation.. The whole reason for trying to keep the O2 out is to prevent oxidation which chemically changes the copper into a non-conductive material (well, much less conductive than clean copper).. You can buy oxy free copper and cut the insulation in a few places (like where it's being shaped around metal edges?) and the oxy free goes out the window (unless, of course, it's TINNED).. The ends are the same way.. unless each strand is tinned, the part that you are using for your connection will oxidize over time.. What do you think happens to battery cable ends (not so much anymore on newer cars, they are typically sealed-ish)?
Now, flexability is a different issue.. But, I ask you, how flexable does a power wire have to be? I have 2 AWG welding wire.. it comes through the firewall and makes a 90 degree bend, the farthest from the wall it is is about 1/2" (inside, then the thickness of the wire comes into play).. then it runs under the dash and makes another 90 degree at the center console.. When I got it (shipped from UPS), the 25 ft of cable was in a loop that was barely over 1 ft in diameter.. Now.. this is welding wire.. Not sure about you, but I've been in shops (dirty places) where the arc welder has been used daily for 8 to 10 years without replacing the cables.. Maybe an electrode holder or cut the end off the wire to get back to cleaner copper.. but still, that's a long time.. And, I'll gaurentee that the insulation on that wire will out perform/last any car audio insulation.. and it's very flexable and it's black (some of us don't like having bright shiny wires
)..
Bottom line.. If you find a 'stranded' wire that carries your 100 amperes for $20, or you can buy some name brand stranded oxy free 'super flexable' pretty colored wire for $75.. guess what... you really are dumb if you buy the name brand wire (unless you really really really feel the need for the color/name).. You will NOT see a difference in the power delivered to your system.. wire is wire is wire (for power applications, and conceding that we are talking about reasonable strand count.. in the context of Wallmart versus Stinger, both power wires will perform the exact same)..
As a side note, you can get more carrying capacity from solid wire of the same 'final' diameter (say both wires measure 1/2" across) as stranded.. why? as pointed out, strands leave gaps.. the solid wire at 1/2" has more material to pass the current with.. The only reason you won't use 0 AWG solid wire in a car is because you kind of need a tube bender to shape it.. hard to do while passing it through a firewall //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif