I feel your pain too.

Biggest lesson here is don't cheap out on parts. For all the time you'll waste jacking around with them, you'd be money and time ahead with the better parts.

I recently installed new ball joints and bushings in my '93 Dakota (2wd) and ran into a similar issue with tightening the ball joints. One was VERY tight when I removed it, thought I was gonna knock the truck off the jack stands because of the length of cheater pipe I was using. Other side was complete opposite. Set the socket and ratchet on the ball joint without the cheater pipe, gave the ratchet a shove just for giggles, and the ball joint turned. Ended up having to tack the new ball joint in place.

I had a local shop take care of the parts that had to be pressed out/in. The first question they asked me when I asked them about doing the work was what brand parts was I using. They said they've had too many problems with off brand parts (I always use MOOG, but even they are coming into question).

As for the tach, it's apparently a Dakota thing. I tried to research it back when I first bought my truck, but didn't find one root cause. Mine works, doesn't work, reads low when it's raining, bounces all over the place when it's cold out. That being said though, mine hasn't been as far off since I replaced the coil.