I take it you're not familiar with the '03-'04 Crown Vic front suspension? It would almost be like bolting in a HDK, Magnum Force, or other aftermarket suspension. Yes, some mods would need to be made but nothing that's going to cost more than $1000-1200 for the whole thing. Steering geometry wouldn't be an issue as the crossmember maintains all the critical points except the upper control arm mounts. However, that is easy enough to make right. Pic below of the '03 Crown Vic type front suspension.
BTW, the car currently has a full rebuild kit, heavier T-bars, and a SSBC front disc conversion but I want better.