I have done both mounts on my V8 and I can confirm that the subframe has to be lowered. I would imagine it's easier on the 6 cylinder engine.
It's not difficult, just a bit tricky using a car jack to hold the engine up. I didn't have a brace.
I actually did mine twice.. The first mounts I installed were ebay special and the vibration was worse than the old ones. So I put them back on..
I my case the vibration turned out to be the AC compressor so I would check all the ancillary spinning components first.
I also installed some tough rubber gaskets between the mounts and subframe to further reduce NVH.