What do you think the limits of the stock EFI wil be?

You will definitely have some tuning to do with those kind of mods...I'd suggest it even with a pipe/filter combo *If this machine is like any other fuel injected machine ever made*

Question though:

Why so high on the compression? 14:1 is getting way up there

Dealerships normally don't "support" fuel injection tuning, it's normally an aftermarket part that does this (Power commander).

If the power commander system is how the LTR does end up working - You'd have to buy a power commander and do it yourself, or bring it to a different mechanic shop and let them do it

Another thing - Once you get over the 13.5:1 compression ratio, those motors start running way hot. If you set it up right 14:1 will run great, but you're going to have to keep a close eye on that cooling system