Depending on what they are and how high class you want them, you might be able to re-do them yourself. I think oil, temp, and fuel just need to be matched to the right sensor to read right. Speedo is probably getting the trans gear right.
I have a mechanical tach that I gutted, and put a electric mini-tach inside. Works great, but not exact, the scale is a bit off - zero is good, but at 3800RPM it reads 4000RPM. Close enough for me and nothing but 2 very small screws in the face show it's not stock.