Replacing Catalytic Converters in a '98

[magno_grail]

A '98 with about 80k miles, the converters are starting to give out the sulfur dioxide smell indicating they are failing. Last smog test passed but high. Owner wants to replace them before they fail. These are the options, ~$2000 each for OEM (illegal to buy used in CA) but CARB lists approved replacements. E-mailed CARB about the replacements, told they do not allow replacing them until they fail SMOG (CARB would prefer you drive a high pollution vehicle than replace the converters early), would have to get referee approval first. Waited a couple months, missed their one unidentified caller reply, E-mailed again, told needed approval from a referee, never got back. That was over six months ago. I am taking no reply as approval.
So, they have about eleven replacements approved. Turns out two (L/R complete from manifold to muffler) have not been made yet (likely never will be) and all but two of the rest will not physically fit. Around five on the list are from the same manufacturer but listed under different company names. Seems obvious someone is getting paid to approve these replacements regardless whether they can fit.
Two will fit, however, CARB's rules say you cannot modify the converter or change the size of the inlet/outlet. Well that is stupid as the openings on the replacements is far larger than the Boxster pipes.
Also the rules state the O2 sensors have to be in the original position which is on the rear cone of the converter which obviously cannot be done without modifying the converter.
Plus the heat shield and support bracket are part of the body.
The point of all this is I am going to make a jig to weld the replacements in, keeping the original front and rear cones and mountings.
Is this something anyone would be interested in hearing about? Already I found the description of how to remove the converters in the Bentley manual is very incomplete.