Just a few comments from my 97 swap:
The difference in motor mount location is about 5.5" farther forward, if you use the existing center pan as the point to start your locating. Doing so causes about a 1.5" too long rear drive shaft when using a NV3550 on std mount. I believe the AX-15 is the same. I soft bolted everything together from T/C forward to locate the motor mounts.
If you replace the input shaft on the T/C, you may have a howler.....I did. I also had an alignment problem with the linkage and went to the Novak cable shifter....best decision made in this swap.
The front drive shaft was okay on mine, but I have a HP D30. I also have zero lift over stock.
As was stated before, all you need to replace is the engine wiring harness and PCM. Plug and play as it's said.
You may experience a nose down attitude from the extra weight up front. I did, and went to 6 cyl front springs. No further issues.
Even most of the exhaust system is the same...easy deal.
Holler if you have any questions