The cam swap is quite easy. Get a new valve cover gasket--you will probably rip the current one and it will seal better with a new gasket. Also, have a new cam seal to put on the V15. When removing/installing a cam, DO NOT only tighten down or loosen one cap at a time. Do it in stages amongst the various bearing caps. Absolutely do not simply tighten down the center cap when installing the new cam. I broke an A cam this way, and sure did feel stupid at the time. That is the biggest thing. otherwise, be careful and make sure you don't offset the timing belt, or else you'll have to take the lower cover off and totally reset the timing. The last time I did this swap it took me about 40 minutes, but the first time took me 2 or 3 hours. good luck on that. One thing though, I would advise against removing the cat, even if there is no law against it. Remove mufflers all you want--they don't change emissions--but cat's help all of us breathe better. When I build a rally car in a few years, I'm still going to put a cat on it. They aren't that huge of a restiction. Anyways, have a good one,

Nate Gundy
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'86 240DL sedan, 260K miles, M46, K cam, 25/23mm sways, 260 front and wagon rear springs; http://valvespringcompressor.weblogs.us/