I did it to my 92 Civic without instructions. But when you get to the core support, it's spot welded to the "frame rails". I just drilled and knocked off the spot welds, then self tapping screwed and bolted on the new core support (needed the car back on the road next day). It's been about 4 years like this, but now when I turn on my A?C, I can definetly feel the front end "tighten" up. So I think the core support is just there for looks and doesn't have as much strength holding the front end together. A strut tower bar is next on my list to help out-I'm not taking off the front end again.

Depending on your fabrication skills, mechanical skills and tools you have, it could easy for you or hard. I guess you could do all the work and have someone weld the support up when you get that far, then finish the work yourself. Good luck.