Adding a cab that isn't the same as the combo (that'll be the 102 STD) is going to change your sound & most likely sound different at different venues. It might sound good, it might not.
As for the combo, I had one for many years & only sold it as I'd stopped playing live. If I start again, I'll possibly get another.
The Italian built ones were around the £1k mark in the shops & had B&C drivers (no idea what the drivers are now). I think folk are willing to pay for that, knowing that it's a solid built combo.
As for sound, it's probably the loudest & best sounding combo I've ever played through.
Blew the old TE 4x10 combo back to the 80s.