My tach is located in the dash right next to the speedometer... it came with the car from the factory. I don't know, I just don't see the need for 2 tachs... Aftermarket ones look really cool though.
I have mine mounted at the bottom of the A-pillar so it's in that gap between the bubble from your gauge cluster. Check my avatar, I believe you can see it in there
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**** that looks obnoxious. i dont know that i could drive around with that thing sticking right in my face like that. if i ever had a use for a ridiculous tach like that, i like where det_riot mounted his.