Your sister's I35 is based off of the same platform as the A33 Maxima (2000-2003) which is considered 5th Generation. Bear in mind that the A33 is the last version of the Maxima built in Japan. The '04s are considered 6th Generation and are built in Smyrna, TN.
But if you really want to be more technical, most of the Infiniti line is actually Japanese Nissan cars. For example, the G35 Sedan is the Skyline sedan in Japan. The I35 is known as the Cefiro in Japan and the Maxima in certain other countries.
VQ35DE is the engine code for the Nissan 3.5 Liter V6. This V6 is also used in the G35, Murano/FX35, Pathfinder/QX4, 350z, Altima, and Maxima. In your sister's case, it has an output of 255 hp and 246 ft lbs of torque.
TSB is a Technical Service Bulletin. For the A33 Maxima, there were (literally) a ton of them. Here's a rundown of the TSBs I had to take the '02 in for:
- Wind noise eminating from rear window
- Bottoming out (Dealer I bought the car from was proactive in fixing that on their own)
- Hood vibration at highway speeds (3x)
- Warping brake rotors (2x)
In her case, I doubt she is going to have to deal with the issues I listed, but she might have to deal with the pinging/dieseling issue since the motors are identical. However, I never experienced that with the '02. All I ever used in it was Mobil 93 and I put a K&N Air Filter in the Stock Airbox.
Here's one thread on the Pinging Issue:
http://forums.maxima.org/showthread.php?t=256929
Maxima.org 5th Gen Forum:
http://forums.maxima.org/forumdisplay.php?f=10
There is a sticky with all of the A33 Maxima TSBs in it