need help removing exhaust!

I just removed the muffler on my 97 teg and i got to the three bolts on the cat. Can I just unscrew the three bolts showing or do i need to remove the heat shield to get to the front of the bolt to remove it? Cuz I'm having a helluva time trying to get the bolts off. they are rusted pretty bad. help!!

i took it to a local garage and they loosened it for me. took them about 30 seconds with a pneumatic. piece of cake after that. love my new exhaust.:D