another simple argument is this:

you said yourself that your CRX tach goes up to 8k RPM, and then the needle pegs. Right? Well...if the B-shitsteen redlines at 8,200K, just rev it to 8k, watch your stock tach, and shift at 8K. That 200 RPM isn't going to make a damn bit of difference, and your engine will be happier by not blasting it all the way to its limit every time you shift. Make sense?

In my opinion, there is absolutely NO REASON to use a humongus tach. I think they look stupid, especially in a street Honda. There's just no need, all they say is that you're begging for attention and that you think your car is a full-blown drag beast, which, in 99.999999 percent of all cases, it isn't. Just stick with your stock tach.