Allen key has never worked for me with end links that have been on the car for a while, especially in New England. I usually grab a pair of vise grips and clamp down on the bolt. Then I grab my trusty impact wrench and zip that suckered off. Works every time. You may even want to use some real penetrating oil, like PB Blaster (WD-40 does not count, fyi).
And if those two things don't work, which it should no problem, you can use some heat. Good luck.
01 IS300 - MSM - 185k mile high club
Currently in: snow mode
BRZ Differential w/ 4.1 -- K&N FIPK Intake -- CXRacing Coilovers -- IS350 Wheels -- Greddy Lip [RIP :(]
Hotchkis Sways -- Megan Racing Y-Pipe -- Spec-d Catback (for now)
"Gotta work on the nut behind the wheel before you start fixing bolts on the car"