the onpoint pod plates are nice, not too heavy but sturdy, and the front bulkheads have full contact with the chassis plate (easier on shims)
you might do best to get the conversion, as just the parts may be false economy. you can still reuse the front end parts, pivots, links. I don't know about the diff, you may need an offset diff depending on your choice of tire.
I hear what your saying, false economy indeed. I wasn't sure if the AE axle could be used with the conversion kit (not a lot of info on the site). If not, the cost of buying the IRS axle really would add to the total.
Since I added the Slapmaster thrust kit to the AE diff, it has been really good, and I was hoping to re-use it. I am using Jaco, CRC, and some Contact pre-mounts.