You do have to remove manifold on catalytic models (Californian ones for sure as they have a larger one I beleive.) The heat shield has only a couple of inches clearance and you can't take it off to get at the wire connections unless you drop the exhaust at the maifold connection. you have to undo all the hanger connections except for last one where you can leave it hanging as you move the front to under the engine. Just pipes or headers you should have enough room. (I'm currently making a heat shield based in the mirror image of a Chevy V8 one I got from Lordco that I'll return after I'm finished with it.) I'll post on my blog when done.
TR7 Spider - 1978 Spifire - 1976 Spitfire - 1988 Tercel 4X4 - Kali on Integra - 1991 Integra