There are reports that the masking tape used on the inside gets too hot and starts to smell. I ran the oven through one heat cycle with the masking tape and didn't notice the powerful odor reported. The masking tape seems to on the outside of the insulation where it shouldn't get that hot. While this is one of the most common modifications, it seems many people do it off of reports of an issue rather than having the experience themselves. I tore my machine down more than most and found a couple of pieces of masking tape I had not seen reported before. Most probably miss these pieces and yet experience no issues. However, it is one of the easiest modifications and the effort could prevent a potential issue.
Masking Tape Locations
The main group of masking tape is apparent as soon as you take off the lid. It covers the top of the insulation cover.
The other two locations are ones I suspect most people miss. To get to them you have to remove the insulation cover and the insulation.
The second location for masking tape is on a strip that closes a gap just behind the top front lip.
The third location is a strip of masking tape holding down a cover to the back fan.