The repair time isn't too bad, if you ask me.
Most good panel shops have a decent wait just to get in, let alone amassing parts.
A few years ago, my missus had a big side impact in her 323 that took out both drivers side doors, B pillar, sill panel and rear quarter. The D/S rear strut and arms were bent and wheel destroyed.
Value of repairs on a $16,000 car; $12,000.
I was sceptical as to whether it would be any good once repaired, but my panel guy assured me it would be as good; or better.
As the panel shop removed the bent pillar, rear guard and sill; the car sprung back to square.
He invited my missus to see it stripped to its socks & undies, and she freaked. He showed us the measurements for the alignment jig, and then measured the car in front of us.
It was basically perfect.
He then pulled the brand new sill and pillar out of their wrappings, and sat them in place; fitted perfectly.
It took almost 16 weeks to repair, but we still own it now; over 80,000km later, and it's as good as it ever was. No problems aligning it, no weird tyre wear, no paint issues.
Done properly, your Stag will be fine.