I've had to readjust my kooks due to catching gravel on inlaws driveway. And again due to age of exhaust. It torques with time and pulls itself.
I've done it in driveway just got to get car up high enough to get extra jack stands under car. Using hydraulic jack and solid to hold in place along with something under center brace.
Always thought that the brace was there to help hold exhaust up when working on it. Other then that it seems useless.
I would try to get the exhaust up high enough so it's not hitting the brace. If its sagging now due to torque it could go lower. Exhaust that big is likely to get hit ever now and then.
Like other post said unbolt exhaust from header flange back and slowly tighten from front to back. Once in position.
09 Pontiac G8GT rebadge to a Holden VE SSv
Rotofab, 1-3/4 long tube w/ full KOOKS exhaust. VMS ecm/tcm tune. CTSV brake Upgrade. CTSV wheels 19x9 on all four.
07 350z Nismo, Stillen headers, injen long tube intake. Leather seats.
90 300zxTT Major build est 450hp on low boost, 650hp on high boost. 99 spec front end, have yet to install the wing and tails.
85 Rx7 12a street port with holley 565 est 190hp