Olddawg, I have a 2001 Jag with a 250 ProXB on it. Mine is setup with a 26P Trophy and will turn it to 6150rpms, right at 81mph on just a “me” fishing day. Fully loaded I lose about 300 rpms or so. As you know, the Jag has lots of storage space on it (especially with the flippin compartment in it) and if you start filling those holes (which are pretty much all on the front deck)with stuff I dont think youd be able to turn a 27 very well – your holeshot would suffer the most. What Ive noticed over the years with mine is that it is very sensitive to weight placement – keep your heavy stuff near the back. Ive moved most all my heavy tackled under the seats and now keep my spare prop behind the drivers seat. These are my thoughts on my boat with the XB. I dont know how much different a regular 250 EFI would turn a prop compared to the XB but I would think it might be a little less willing, which would make me more concerned with going much higher than a 26P. Im not sure where you live, but if you live anywhere near Birmingham, Alabama Id be willing to let you have my 26P Trophy for a little while to do some testing. Later, Brett