Well Robin,
Welcome to the real world forum on OHS and BAV.
Re: the scar, have scanned your blog and the picture posted and is likely the worst OHS scar I have seen yet, if it makes you feel any better, the picture is likely taken about 2-3 days post surgery by the look of bruising & all, so yes there will likely be a scar and yes it may not be pretty for 1st few weeks, but it does get better quite fast and you will eventually wear it proud, as it likely a result of saving your life. You will notice that the patient looksvery much alive though (grin)
For breathing tube and most of us, you are so dozed up in 1st day, that you will hardly notice it before it is removed, you will only have short periods of consciousness in 1st 24 hours and if I remember well, while breathing tube, there is no need to cough, so it is actually a blessing, but if you are concerned let the surgeon know before surgery.
So chin up, read up pre op post op threads and welcome again to an excellent support group, ask and ye shall be informed
all the best