I ordered a black pickguard for my SUB 4 and should be recieving it this/next week from EB. My SUB is also white and I will post a pic when I make the PG change.
SUB 5 PG's are their own beast. They are similar to the SUB4/SR4 PG. Call customer service to see what they got. If not, Google it to find other places that sell them.
Those 'cardboard' pickguards are even worse on a white sub (IMO). I think a tort one would look better. In fact, I would like a tort one too on my textured graphite sub. Another guy on this forum (forgot his name and too lazy to search) had one on his textured gaphite fretless sub. Looks amazing. Don't be too worried about it. Sub's do rock as hell, yeah. I've never played a better neck.