I installed four shocks and springs and LCA relocation brackets and tried my best to torque everything but 1) the torque wrench I have is a piece of crap and 2)I couldn't reach all of the bolts with it.

The two things I'm most concerned about are

-the LCAs and relocation brackets which I wrenched on with all my might.

-and the top of the rear shocks which I couldn't torque down. I didn't wrench on those too much at all because they call for 18ft lbs.

So how important is using a torque wrench on this stuff?

 

Too tight, they could weaken/break or deform mounting areas. Too loose, they might come off.
Isn't a new torque wrench worth the cost of knowing you have properly tightened the fasteners of assemblies that hold your car together while going down the road?

 

Wrenched down with all my might means different things depending on what you used (how much leverage you had)
Top of the shocks I wouldn't worry too much about as long as you compressed the bushings some
A new beam type 1/2" drive torque wrench shouldn't cost you much and they work fine for that kind of stuff

 

If you are going to do work yourself you should be following the OEM specs by the manuals. I spent $50 bucks on the F-Body manual, and probably $125 on my 2 torque wrenches, my favorite tools, those manuals are life savers.