Obviously with added oil/larger sump the oil temps and similar are beneficial to the cause depending on use.
Snowman & Scotsman both ran stock sump'd GTR's for 2-3 years no problems in that department. Motors were stock too and eventually the died but that's what happens @ 330-360rwkw over a hard life. Since then they've both used N1 pumps, as have pretty much all Vic cars. Not one has broken a pump yet. Most motors hand together fine as well (failures are not pump related).
So if you are a bit worried then swap out the gearset. They aren't too expensive and if you get piece of mind then that's covered off.
Comes down to cost really:
Option 1 - 1500 Closer to $750 if savvy Billet gears from JPC.com.au $350 can be used
Option 1.5 - 2300
Option 2 - 3200-3500
I'd also suggest if you are going to go all out on a pump, that you use the Tomei one. It's the only one that utilises a different gearset arrangement similar to that of the 2JZ (never hear of them breaking pumps). It's something I've never really worked out why the other aftermarket pump makers don't use the Tomei/2J style as for a bolt-on pump, it's the way to go.
Thank you R31 Nismoid for the answer above its a very valuable and credable answer