intermittent speedo and tach

So, my wife fell in love with her '99 zx2 at first sight. I tolerated it until I banged second the first time.Anyway, I drove it home 6 months or so ago and everything worked. It sat till about a month ago, and the tach works sporadically, and the speedo not at all. Any ideas? I’m guessing both are of the magnetic pickup variety,but,being that the drive axle is on the “wrong” end of the car from what I’m used to, I am a bit lost…
I guess ,while we’re at it,I should also ask what’s the most tire I can fit under “her” car?I’m looking at a set of 16x7 rims and 205/50-16 tires…What good would stockers be with the Energy Suspension chassis kit,and, all these crooked country roads in rural wisconsin ?Thanks a bunch for any input! Andy

My first thought for your speedo problem would ve the VSS sensor.

As for tires, I have 16"X7" rims with a 205/50/16. Stock wise you should not have any fitment issues. If you lower it you might have a little rubbing on the fender lip. Which I just took care of this problem on my car by rolling the fenders with a fender roller.