Upgrade? Ax Change?

Well, Rondo Music has this new P/J bass on their website.

Anyway, was thinking of getting one of these and changing the pickups and the brdige. Going for a Powerful P, and a nice J growl to accentuate it, read tons of reviews and most people say the Duncan Quarter-Pound set is an excellent buy. Though i wouldn't mind the vintage tone of the Antiquity II set either, anyone know if its hum cancelling, or had any experience with the? And probably throw a Badass II bridge on there. And some new knobs

On the whole it will run me about $300 or so, with all the shipping and installations and hardware upgrades.

The kicker is, I would sell my T-40 to supplement the cost. I've been playing some P/J's recently through amps comprable to mine, and the T-40 just doesnt get that P "thump" I like.

Im basically asking for your opinions on if you think this is a wise move or not. Or if you suggest any other pup combos or bridges, or upgrade options.

Also, How hard is it to install a new nut on a neck? The nut on this thing is plastic, so I was thinking about going with a graphite one. I'd pay to have it put on at a music store, just curious what about it shoudl run me.

Also, the P/J is much ****ing lighter than the T-40(by about 4.5lbs).