Need new engine mounts?!

[vikon]

Hey,

I have an 1996 G20 with A/T. Recently I noticed that my rear engine mount was cracked, and my left transmission mount is leaking black fluid...From what I've read in the previous threads black fluid is a bad sign of a mount going bad...There is also some vibration at idle, and reverse...
I planning on replacing those myself, however I'd like to get some advice on the job, and I have couple of questions...Is it possible to do (I'm a little concerned about the left one, it seems like it will be hard to get to it)? Can I use a regular jack stand for support? If anyone has a manual, what are the torque specs for the rear and left mount (including the brackets if they have to be removed)?
Also, can I use aftermarket mounts like Beck/Arnley instead of OEM? They are way cheaper...

Thanks in advance! I'll appreciate any input!

Regards,
Viktor