my few 2cts.....
i think myvi and sawy (just don't wanna type v twice) are of two diff segment, myvi is more to small mpv/minivan class (like getz, picanto) whilst sawy is more to hothatch/pocket rocket class (like previous swift and mirage cyborg (the boxy one)) .
myvi's look is more to leisure and comfort driving whilst sawy is more to pacesetter gogetter type (sawy have the silhouette of VW golf, anyone agree?)
power wise sawy only hv bout 70+ ponies whilst myvi is 80+ and the power to weight ratio is myvi gain
interior design wise, myvi design is very practical, ergonomic and user friendly whilst for sawy........... hard to say..... only the blind can be pleased
for upgrading and customising, i think myvi is a better choice, with the toyota powertrain and the cousins available (aygo, boon and one by pug shares the same platform), myvi is a very big white canvas to draw on.
bout sawy, i'm a bit blur bout its source, initially i thot it'll be based on mitsu colt (and it should be but dream didn't come true) then maybe it is based on any Renault PSA model (i'll never believe that it is our own design, if it is, then
the design would be much uglier). if it is a renault, maybe there'll be Proton Sawy-Clio V6 one day for the tuner head. WOW! surely an asskicker!!