Do a black cooktop and the stainless frame. It will give you the look of the "stainless" rimmed cooktops.

Not having the specs in front of me to see exactly how much size difference there might be, I just have to offer than the cutout dimensions are usually not quite the same, but usually the overall dimensions of cooktops are not widely off. As long as you get about 1/2" of lip on top of the current cutout, and there isn't an actual gap then you'd be fine. If there is a gap, if it's small, if you shift the entire gap to the back by pulling the cooktop forward, then you could just do an applied Corian trim piece on top of the counter, sorta like a quarter round at the rear. Or just a stainless trim at the rear.

Thanks live wire oak.

My existing cut out is 29 and 3/4 inches by 20 and one quarter inches. The Bosch installation guide calls for a cut out that is 28 and 3/4 inches to 28 and 7/8 inches by 19 and 7/8 inches to 20 inches. The cooking surface of the Bosch is 31 inches by 21 and 1/4 inches. The drawing makes it look like the cooking surface is slightly larger than the surface that rests on the counter top. If I've done the math correctly, that would leave 1/2 inch lip on each of the long sides and 5/8 inch lip on each of the short sides, if the bottom of the cooking surface is what actually rests on the counter. I've been told that I should not allow the screwed in brackets to be used as that may cause a crack in the Corian.

The questions to be evaluated seem to be:

Is the overall size of the new cooktop larger than the cutout? If yes, then it won't fall through. This seems to be the case from the dimensions.

Is the overall size of the support part under the cooktop, if any, large enough to support the unit on all four sides (with an adequate support surface). If yes, then it will be supported. This condition is unclear from the information above.

Then the next question is what to use to keep it from moving back and forth in the cutout? One could bond in almost any material that is no more flammable than Corian, such as blocks of Corian (don't need to be neat as they won't be visible, blocks of redwood or ipe (not easily burned), blocks of aluminum, to name a few. Adhesive that bonds to Corian is needed in all these cases.

By using only blocks, instead of a major Corian finishing operation, the installation space can be recovered if necessary at a future time, and the cost is considerably less.

kas

cyalexa, we're now facing the same exact problem. How did you resolve yours, and how did it turn out?

I had an aluminum frame fabricated. It sits on the Corian, the cook top sits on the frame. I am happy with the outcome and very happy with my cook top. Good luck.