I generally use the "two finger" rule, if you can put the index and middle finger over the fastener to be tightened, you will usually have enough room to install and tighten the fastener from above. If not, you will have to use a torque extension and a lettle math to measure offset length and how much to decrease the torque (trying to be as close to fastener as possible). You may have to remove the heat shields in order to access the bolts on all the flanges, and use antiseize compound, all that heat and corrosion will make things tough the next time. You will probably need to look in the service manual, as I do not believe the owners manual covers the torque value (but check it, sometimes you'll be lucky).