If you can afford it, get a mod fast. The Isis was long discontinued. Many of the components are obsolete and very cheap quality. In around 2008, most jurisdictions required the replacement of the Kevlar cables with thin version of conventional wire cables, which grudge (turn red and deposit shards) easily. The controllers often lacked a UIT interface, leaving competitor companies with only one option, IMS laptops. Many of these models came with the machine and drive installed in one of the worst places possible, the pit, which i vulnerable to water intrusion and flooding. Worst that that, they were very noisy.
Due to the compact size of the average ISIS shaft, the only things that will be able to replace it will be the Schindler 3100 or 3300 due to their compact size. A gen2/gen3 underslung may also fit, but not overslung. You might also be able to fit an above ground hydro in, but you might have difficulty finding room to accommodate the pit can.
Good luck finding ISIS parts. The only place you might find any is Vertical Express.