Ok Guys Im From Australia And I Own a 2001 Nissan Maxima, They Are Almost the same as your 2002 I30's I believe. The A33 Shape..
Anyway its an Automatic, When it shifts, slightly from 1st to second, Big Problem With 2nd to 3rd shift... The gear box "flairs"...
just wondering if anyone else has had the same problem with the box. basically it involves the gearbox seemingly overholding gears then clunking (not heavily, Yet) into the next gear..
Any ideas on the problem?
Also as to fix it, it apparently needs to be completely removed im just curious as to ways to strengthen the Automatic for Future Forced Induction..
Its Current strength seems as though it would fail pretty quickly

 

There's a TSB on that issue of it lagging between shifts, especially during WOT. It is covered under warranty (assuming you still have yours). I took mine in and they replaced some valve and it fixed it.

 

Sounds like yuor having the same problem I was having, when I would really get on the gas it would hold off shifting then slightly gerk into 2nd and sometimes 3re. It was my mass air intake. They where out after a while and some have told me that they have a defect in them. Have it checked out. Cheaper than tearing the tranny apart.