A full door swap is not a weekend project, and we'll say that plainly. Pulling an old torsion-spring door and setting a new one means working under load-bearing cable tension that can break a hand or worse if the winding bar slips. If your door is from the original 1989 build and still has its original spring, that spring is well past any reasonable service life regardless of how it looks, and that's the part that bites people. Where DIY makes sense is cosmetic: swapping hardware handles, repainting panels, adding weatherstripping at the base. Where it doesn't is anything involving the spring, the cable drums, or re-squaring a door in an opening that's shifted slightly over three and a half decades of settling, which is common in this area's housing stock. If you're set on doing part of it yourself, at minimum let a tech disconnect and remove the old spring assembly first.