Your half way there! I replaced my belt and tensioner a few months back and motor mount bolts. I'm wondering how hard it would be without taking the mounts out. Do you think there's enough room to be able to loosen the tensioner to get the belt off and room to torque down the pulley bolt without removing the motor mounts?
I usually use my weight and stand on the breaker bar to loosen tight lugs lol surprised the impact couldn't get em. I looked up that Bauer corded impact 300 lb. Says 1050 breakaway torque. Would think that should easily get the lugs loose. They even show pictures of taking off lug nuts. On sale for 69.99
www.harborfreight.com
I usually use my weight and stand on the breaker bar to loosen tight lugs lol surprised the impact couldn't get em. I looked up that Bauer corded impact 300 lb. Says 1050 breakaway torque. Would think that should easily get the lugs loose. They even show pictures of taking off lug nuts. On sale for 69.99

8.5 Amp 1/2 in. Impact Wrench with Rocker Switch
Amazing deals on this 1/2In Electric Impact Wrench at Harbor Freight. Quality tools & low prices.