Right now, it's probably Jason over at Eurosport. They've done several lifts, updates, & are familiar with the B58 engine. I've used them, & Mossy IG was referring their IG owners over to them.
Top notch mechanics here, & the shop Jason runs is a living masterpiece of new & vintage European vehicles. They don't do collision.
No idea when Arrowhead IG will be up & running.