I agree that it isn’t as necessary as it used to be and that it’s all about the TJIAB these days. But I’ve had SA do the Carry Action Job without an SRT upgrade. And then the same on a gun that already had the SRT installed from factory (so I’d still count it as him not replacing anything). The only thing I haven’t tried from him is the QTR.

Grip tape here, extended magazine base plate there, grip swap, professionally done action work.

By and large I don’t do stuff that can’t be easily reversed. Rather than drill and tap a shotgun receiver I’m seriously considering buying a new gun that has already been altered, foolish isn’t it.

I modify somethings on firearms, most often I'm repairing/replacing old springs/etc.

Other than straight replacement, mostly I upgrade/change triggers, add/replace night sights, add optics and change furniture.

I haven't refinished anything but CCR makes me want to looking at their work.