Superdrive failing advice needed

I have an Intel iMac, can't remember the model but it was the white one released just before the new silver ones, which I bought nearly 2 years ago. Everything has been absolutely fine except that for the last week I am unable to burn DVD's (although it will happily still rip CD's play CD's and play DVD's just won't burn). Toast gives me a bunch of Hardware errors and Sense Error's with various codes, Finder fails too and says that it can't communicate with the burner and googling all the errors shows that it's either media, dirt or the drive failing.

Well I'm 99% certain it's not media as I'm using the same discs I've always used without a single faulty disc in the past and have also now tried 2 other brands both without success.

Dirt could well be the cause as I'm currently ripping all of my CD's and so far have done around 250. Some of these discs are quite old but I have been trying to clean them first but it is possible that some dirt did get inside. I've tried using cleaning discs (didn't expect them to work) but that didn't make any difference at all so maybe it's not dirt or the dirt is really stuck on.

This leaves me with either dirt I can't remove or a faulty drive, either way I'm looking at a replacement.

I've just contacted my local service center and they are quoting £150 + parts + VAT! Wow, so around £200 to replace a £20 part!!

So questions:

1) Yeah I know it will invalidate any warranty (which has expired) but has anyone tried replacing a Superdrive on an iMac themselves? I've built dozens of PC's before so I'm not a total newb when it comes to hardware but is it advisable, worth the risk or just plain foolish?

2) Assuming that the answer to 1 is a resounding NO!!! The other option is just to spend £35 -£50 on an external burner. However, is it possible to configure the eject key on the keyboard to eject the disc from an external drive or is that only possible with internal? Are there any other configuration/operational issues with having 2 DVD drives on an iMac when OSX doesnt know that one of them is faulty?

3) Why didn't I buy AppleCare when I had the chance?

Peakoverload said:

I am unable to burn DVD's (although it will happily still rip CD's play CD's and play DVD's just won't burn).

2) The other option is just to spend £35 -£50 on an external burner. However, is it possible to configure the eject key on the keyboard to eject the disc from an external drive or is that only possible with internal? Are there any other configuration/operational issues with having 2 DVD drives on an iMac when OSX doesnt know that one of them is faulty?

Click to expand...

Dealing with just Q2 for now, the majority of other posts about faulty internal optical drives recommend going with an external drive. Pioneer brand is highly recommended because it works so well with MacOS.
The key combo command for ejecting from an external drive is Cmd-E.
Because an external drive is cable-connected, there is unlikely to be a conflict or confusion about internal vs external drives being recognised.