Yes you may want a heavy duty torque arm....The
panhard bar you can do in your garage but you will need a few extra hands at certain times during the project. Air tools are recommended and you will have to buy some plumbobs and take some accurate measurements. The torque arm...if you don't have a lift and a good welder I wouldent recommend doing that at home. You can get the instructions for the installs on MM's website and there very detailed...read thru them and see if you want to do it yourself or have it done.
The PHB provides excellent control of the rear axle (thats its job). Due to the soft stock bushings in the upper arms the axle can move sideways under the car under hard cornering which causes an aukward feeling (seat of the pants) and tends to reduce your ability to control the car. Stiff busings in the upper arms will cause
suspension bind so thats not a good alternative. PHB or a watts linkage is the best way to go.
A torque arm is used in conjunction with the PHB and allows the removal of the
upper control arms alltogether. It controls pinion angle changes (the other job of the UCA's aside from lateral axle location) and is bind free unlike the stock desigh upper arms. A bind free rear
suspension is great for consistent handling at the limits. The torque arm creates lots of rear grip (by resisting pinion angle changes) so the car will launch harder w/o spinning the tires and you will able to apply throttle sooner and harder coming out of corners. A product that produces a silmilar effect is the evm tri-link whis is similar in design to the upper link on the 05+ mustangs. BOth TA and 3rd-link pieces also have the effect of improving the anti dive geometry of the rear
suspension among other little things.
Either way the UCA's are supposed to control lateral movement and pinion angle changes in the rear
suspension and there not good at either and they create bind by nature of their movement. A PHB (or equivalent) and TA (or equivalent) will seperate the jobs of the UCA's and do them much better. Thats as simple as I can put it without getting very technical.