Been there, done that (that is, had it done). Definitely use an aftermarket. Make sure it's all copper. The aluminum factory ones were the ones that corroded.
In my opinion, not a DIY project. It is very involved and not for the faint of heart. Best to find an independent in your area who has done a number of these as there are some tricks.
Somewhere on the site someone posted pictures of their dash disassembled. Not a pretty picture!