No, I won't be running cats. The car being over 25 years old is not subject to emissions testing here. You have to check the emissions requirements in your area.
You can run power steering but you'll have to convert it to rack & pinion as there's no room for a power steering box. The...
6.1 or 5.7? Not a bad price either way. Make sure the wiring is there and intact.
Guys with lightly modded 6.1's in 4100lb LX's are easily going low 12's. Take about 1000lbs off and do the math. 'Nuff said!
The cons are high price, added complexity and possibly limiting yourself to manual...