i had to call Redline and they told me the distributor of their products in town. i bet you could look it up on their site.....
local speed shops should have Redline products, but they may not carry D4...
i prefer the D4 cuz Redline makes a number of ATF products, so they are more application specific. i dont like "one product fits all" normally.
that said, i use M1 ATF in other cars and it is good......