Paul
Only you can decide if you "need" the torque wrench.
I'd guess 99% of people do not use them.
I'm neurotic, but I can guarantee my drainpan threads are less likely to strip.

The oil I removed was fairly dark after almost 5000 miles.

Thanks for the heads up on the transmission fluid.
If mine, 2004, manual recommends something as elaborate as filling and draining 3 times I'll do it myself.

Need fewer troops to support.
Drive a hybrid.
Best tank 71.65 MPG.

Before this car I spent two years learning hypermiling on my 2004 HCH1.