Although not many have completed this swap thus far, it has proven itself to be a far more potent solution than the MEVI. The MEVI, however, has it's own advantages.
Advantages
00VI...
-Low RPM power. Rather than lose power at low RPM's over the USDM manifold, the 00VI actually gains a significant bit of power.
-Midrange and high RPM power. Although the 00VI and MEVI are both variable manifolds, the difference in operation and design simply allows the 00VI to outflow and outperform the MEVI even as RPMs climb, resulting in even higher peak numbers.
-Ease of finding parts. Because the 00VI was used as OEM equipment on 2000 and 2001 Maximas in the US, parts are easily accessible at a Nissan dealer or in junkyards.
MEVI...
-Ease of installation. The MEVI has many similarities to the USDM manifold in terms of design and layout, and was meant for a 4th gen engine. It is basically a bolt-on part.
-History. Simply put, people have been using the MEVI on their cars for years and years and there is lots of experience and knowledge regarding it.
-Parts. Almost all of the parts off of your current 4th gen can be re-used with the MEVI.
Disadvantages
00VI...
-Installation and preparation. The 00VI is simply a much more daunting task. It requires modification to the manifold, wiring work, many custom parts, and a lot of time.
-History. Or it's lack thereof. The 00VI swap is still relatively new (by comparison) and very few people have done it.
-Parts. Almost nothing from your 4th gen manifold can be re-used, and even re-using your stock 4th gen intake becomes a task that involves ordering parts.
MEVI...
-Power. It doesn't make as much peak power, and you actually lose low RPM power as a result of it's design.
-Parts. They are hard to come by, and often must be ordered expensively through a Nissan dealer and require a good wait to get, due to the manifold never appearing on US Maximas.
On the Dyno
Boosted...
(Stephen Max's car: 14.3 tq, 13.2 hp over MEVI and gains from 2500 rpm to 7000 rpm)
All Motor...
(BSwithTF's car: 11.45 tq, 8.61 hp over MEVI, and gains at every rpm)
200 WHP vs. 200 WHP
(jenk01SE's car [00VI] vs. Zack342's car [MEVI])
Video comparisons of the 00VI against the USIM can be found, courtesy of .org member 99BlackMaxMS, here:
http://forums.maxima.org/showthread.php?t=555252