I have an 89 745 turbo with AC but I do not like the old style climate control panel with the slider type temp control and no recirculation or AC switch. Will the newer 3 rotary type controls in the later 740 and 940 work in my 740. I sure would like the additional control that this gives. I do not need or want automatic temperature control, just the recirculation and AC on/off controls. Will this unit hook up to the wiring and vacuum controls from the 89 or is there substantial modifications required? How about substituting the newer dash panel to fit the three rotary controls? Has anyone done this?