Need help with 928 dash
 

Will a '89 dash interchange with a '87 ?SmileWavy

yup, dash is same from 77-89

....um, didn't the 89- dash incorporate the digital display? I don't think they are interchangable...

we're talking dash not instrument cluster or pod... the pod itself only has a couple variants, and early pods can be converted to later style
dash only has 2 styles, airbag and non airbag... and the airbag dash can be altered to use in a non airbag car
center console only has 2 true styles, 78-79 w/out temp sensor and 80-95 with temp sensor

Gotcha...

Can you then fit airbag versions to OB's and get them working, or is there too much plumbing to be done?

not sure it would be worth the trouble, you'd need bags/controllers/harnesses/sensors etc etc

USA has a bunch of regulations related to the air bags, that might limit what can legally be done as well as what's practical to be done.

Airbags can also deploy under fairly minor conditions, and the amount of damage can total a 928. Start with the dash ripped apart and the need to replace the airbags, add to that I've heard the windshield often pops out on to the hood and fenders.

Strong feelings both ways on 89 vs 90.

How hard is it to replace the dash and what alls involved?

Don't forget the allen bolts (3) at the steering column hinge on the bottom. Be careful, they strip easy.