I'm a Toyota fan really, but I think the Nissan VH45 has a leg up on the 1UZ.
My good friend just destroyed the production car land speed record set by the Nissan Factory Team in a 300ZX (226 mph). He has been flown all over the Western hemisphere tuning Z cars. Certainly an authority. We've spent hours examining the differences between the Q and the 1UZ
The bottom end in the Q45 is 6 bolt like the 1UZ, but the main studs make the 1UZ studs look like tooth picks. It looks like something you would find in a 6-bolt Donavan, Brad Anderson, or some T/F engine. Of course, this is to accomdiate the over-built reciprocating assembly. The crank is forged, as are the rods, and you can clearly see the forging marks, (unlike ours). But, the pistons are considerably heavier, which explains the reason for the beefy bottom end. If I remember correctly the Q's were 30-50 grams heavier. They have a full skirt unlike the T shapes my 1UZ had.
BTW, if you weren't concerned about the weight we could easily use the Q rods.
The heads have a really wide valve angle. You can only see the tops of the valves looking down in the intake ports because they're canted out so much. The cams are independently adjustable (I really don't find this feature that compelling). The valves on the VH41 are titanium. The heads flow good aparently, but have the casting features to be pushed further than the 1UZ.
I'm not down with the cam followers (like on the other Nissans) and this was a little bit of a disappointment for my friend as well. He thought the shim and bucket was far superior until high lift cams were used. Then the casting around the bucket possibly becomes an obstruction.
With all of this said. How come the Q hasn't caught on yet? The 1UZ has already been in the 6's at over 200mph. Where's Nissan? (Insert cricket chirping noises here). Did you look at the engine homologation for the Grand Am series?The advantage was certainly given to Nissan, not even a question.
By all means the Q45 should be the engine of choice when using conventional means. I think the 1UZ is one of those engines whose whole is greater than the sum of its parts and I'd still rather have the UZ.