Do yourself a favor. Unless you have a lot of time and tools and a great place to work on this save this one for a pro. I have seen photos of 140's with most of the interior out on them. One wrong move and you can break expensive to replace trim and plastic. I have a feeling that most local shops don't even make a lot of money on this because of how time consuming it is.

The upside of having this done is knowing that you won't have to have it done for a while. If you keep the paperwork and intend on selling the car it could be a prospective selling point to a new owner knowing its been done recently. I try to put repairs like this in perspective. It might cost you $2000+ to have the dash pulled out but you likely won't have to have it done again for a long time.

It could be worse every 30K miles my Porsche has to have a $1500 timing belt put in it as part of its regular service. I have a friend with a Ferrari Mondial who spends $15,000 every 30K service because they remove the engine and transmission.