I bought my SR300 because I like green, and it came with a rich, bright Sparkle Green finish (I'm with ya here, Ursus).
It also helps that it has a very smooth neck. Don't get me wrong, the thin profile takes a little getting used to, but the satin finish on the back is nothing short of sensuous! I'll never buy a bass with a gloss-finished neck ever again!
As for a thumbrest, I'm having no difficulty anchoring my thumb on the middle pickup. Then again, I have large hands...
The pickups sound pretty good-- smooth when I need them to be, and punchy when I need them to be. so I'm keeping them for now. But, maybe some time down the road, I might consider a set of Nordstrand Big Singles or something, assuming they'll fit...
As for the woods, I've never heard of Agathis before, but it resonates pretty freely, especially in the mid-midrange (D and G strings), though that could also be the strings. But, the 5-ply maple/rosewood neck is very nicely-done, very even, and very clean. Did I mention it feels like silk?