A lot of folks recommend heat for the subframe bolts, but I would urge you to simply have it ready in case you need it. These bolts are quite hardy, and hand strength should not be sufficient to break them. Heat is a last resort as I've learned.
In fact, it may not be necessary; it wasn't for me. A good 1/2" Drive breaker bar will do the trick. You gotta use some muscle, and when they get stuck you'll find they bind but release (pop) 15 degrees or so at a time. It might take you an honest hour getting them loose.
Calipers and E-Brake lines have to be removed/disconnected as well as the exhaust obviously... Unplug the speed sensor cable(passenger side next to the gas tank). Disconnect the driveshaft using the bolts (not the nuts and bolts. It's better that way. Then remove the bolts.
Three jacks make it easy if you don't have a special jack for the differential to lower it correctly. Two go under the upper cradle bushings, and one on the front of the differential (the body). Once the bolts are out and you attach the jacks in the back as you remove them (first), you'll want to gently lower the subframe. It pays to take the rotors off, but you don't have to. It's a weight thing.
You'll want to tilt it by lowering the back first so you can more easily release the SUPPORTED drive shaft from the differential. There's a dowel pin. It will take some convincing to get the frame to move. Then you simply lower the three jacks in succession.
These are floor jacks, and I recommend big ones if you can borrow them. Watch for the differentials vent snorkel, and then once you get it low enough you can pull it out.
First time takes a while, but putting it back in will take 15 minutes with 2 people. It's a lot easier once you know what you're doing.
Again, supporting the driveshaft is critical.
Removing the cradle bushings is easy enough with a self made press using threaded rod, a plate with a hole in the center helps... washers, and bolts. I used two on the side I was turning to lock them in place. I also used PVC fittings as a sleeve. I forget the size, but you can measure that easily enough once the cradle is out.
The rear ones will pop out. The front ones will rip out leaving the sleeve. You simply use a hack saw to score the plastic in two places about 15 degrees apart. By score, I mean cut enough that you're nearly through, but not all the way. It's a plastic sleeve; after that it'll tap out pretty easily once you score it.
It's a breeze when done right.
Any other bushings are best using a ball joint press (C-Clamp looking thing if you're not sure). The differential is hard to get out of there if you do those, and those sleeves are metal. So if you can't press the metal out, it's a beeotch to remove with a hammer and chisel. You have to be sure to go the right way, too, because it appears to be ever so slightly expanded on one end to prevent it from moving.
Anywhoo, it's not an extremely difficult job, just time consuming and you are best doing the removal and reinstallation with 2 people.
'09 PSM G8 GT - OPG Intake, DOD-Delete w/ Stage 1C 218/229 .600 Lift 117.5LSA, Kooks 1 7/8 Mids, Solo Axle-Back w/ X-Pipe, SuperPro Bushings (Front and Rear). BMR Sway Bars (Red)
"If you want to criticize someone else's work, be sure that your own is in order first."