Considering this is pre-resurrection, I do think Exar has a solid chance. If things get long and grueling enough, then the vong symbionts will take their toll. Krayt can fight for a long time even with them, but it's a danger against someone of this level.
Save in the HtH round- Vong physical enhancements give Krayt a solid advantage there either way.
Once he was returned, Krayt- 1) Gained new techniques, Dark Transfer and shatterpoint. 2) Had his strength in the force increased, since he no longer had to fight the vong implants (though he still had the beneficial ones like arm and eye) 3) Lost the backlash effect of pushing too hard for too long, his endurance is greatly improved.
He does, flipside, lose the protection of the armor, but I would say it's a nice boost.