So there's a couple of things here. One is what the actual law applicable is. Smog regulations are usually more administrative, which relates tot he registration and title of a vehicle, and as such, Canadian citizens are out of the local baliwick. If they're going to allow a Canadian registered vehicle on their highways at all, then they are accepting that it meets the administrative standards required in the province of registration, unless they can prove otherwise. California may have laws for DRIVING without one, but all I've been able to find are laws for California residents (Except in certain rural areas) to abide by CARB regulations to have their car smog certified, which is required for registration.
As for federal law, I found this: "The federal government says you can't touch the converter unless the original is missing or damaged, the vehicle is older than 1996 and has more than 50,000 miles or it's a 1996-and-later vehicle with more than 80,000 miles." This appears to refer to federal emissions standards (Though it may vary from state to state) and would indicate that a 1988 vehicle with a removed cat isn't a problem for the federal government.
So let's say that I'm a Nevada resident, and I have a car, licensed and registered in Nevada which doesn't meet CARB regulations. If I drive into Los Angeles, am I going in there to "commit murder" simply because my (for the sake of argument) BRAND NEW CAR wasn't manufactured to California standards? Certainly I couldn't have registered it as a Los Angeles resident, but does that mean that I can't drive it there?
If my Supra were totally, completely 100% stock, it wouldn't meet California standards, since my car would have needed a second catalytic converter for California emissions standards in 1989. Would that mean that I couldn't drive it into the state even if I'd never made a single modification from stock, even if it were brand new? Seems unreasonable. I'd accept if I could not register it there, though If I were to move there, I could probably have applied for an exemption for a car of that age.
So as far as I've been able to determine, a catalytic converter could be reasonably removed from a 1988 vehicle and still meet federal legal standards.
As for California standards, that 3" high flow cat wouldn't help you. It's every bit as illegal as none at all where their laws are concerned. The only thing that they would accept at all is having two (Since your turbo car came with two) cats in the OEM positions, and those only from a select list of approved models. (Since my car only came with one as an NA, I wonder how that would apply to me. Being reasonable, it should go with the motor, but reason has long since left the building, and it may go with the chassis.)
Another issue entirely is enforcement.
Around here, it's illegal to have tint on any window forward of the driver's seating position. This means front door windows and windshields. Tinted front windows are not at all uncommon here, and people get away with it for years on end. Generally when I hear of people getting a tinted window ticket, they've attracted police attention for something else first. I think the question also related to the likelihood of getting pulled over for a smog check, assuming that he's done nothing else to attract the attention of a local officer. I can't answer to that, or even give any educated speculation.
Oh, what I can say is that the entire province of BC does NOT have Air Care, just the Vancouver area does. My father lives in BC and doesn't have to pass Air Care (Though his vehicles would anyway.)
