The conversion could of been bought on a cost basis, as in 'for-sale, 250kw L28 engine package with 500nM of torque, only $5000'
Then to get the same for an RB/VG conversion would b up to $10,000
hypothetical of course.
My pick would be a VG30DET, and the VQ series too.
I have 2x VG's inthe garage, still NFI what to do with them though