Yes in 8.21 it is a transition. If you want to do it in M100i you’ll probably want to put your clip in a new program and put the clip on top of itself > pick flip horizontal > render the transition and then import the new clip.
In general 300dpi at the actual size you want it to be will be pretty good.
Realize though, as a raster image when it is scaled up- whether in PS, Illustrator or Adobe Acrobat – It will start to get blurrier and lose some detail.