OEm wires are fine. you can spend $$$ on some aftermarket ones, but the OEM wires work fine.
for plugs, use ONLY NGK plugs. I've tried everything under the sun over the years and our engines really do best with the NGKs. and for $1.50 a plug, it's not worth the hassle of looking for something else.
on the oil, the VG is spec'd for 4 1/8 qts US (3 3/8 qt Imperial), 3.9 liters WITH oil filter change.
for daily driving, just dump in 4 quarts or liters and you'll be fine.
for track days or auto X or anything like that, I always dump in an extra quart to prevent air getting sucked into the pickup and cooking the rod bearings.