Long time lurker, first time poster here. I have researched oven and cooktop choices to death, but can't seem to find an answer to this dilemma and would appreciate any feedback.

We are doing a mini (and very tight budget) kitchen remodel, and plan to replace only the countertops, gas cooktop and electric wall oven. Space and budget constraints dictate that the current setup remain: 30" gas cooktop directly over 30" electric wall oven. Currently have a 13 year old GE cooktop which I loathe (grey burner grates that simply will not come clean, chips, dying igniters) and a Ge electric oven that I am not crazy about (loud cooling fan, uneven temps, slow to preheat). I have a child with multiple food allergies and do most of our cooking and baking at home, so I would like something reliable and budget friendly, preferably with convection. In reading through the GW posts, I narrowed my wall oven choices down to the Electrolux (with wave touch) or the Bosch series 500 oven.

The problem is, I would like to use an older but unused Thermador gas cooktop (SGS model) given to us by a friend over the oven. Neither Thermador nor Electrolux have been helpful in answering whether this can be done. From the installation instructions, it appears that they will fit together (though I am not totally sure about this), but both company reps tell me that this is "not authorized" and could void the oven warranty.

Is it advisable to do this, or should I bite the bullet and shell out more money for a cooktop of the same brand as the oven?

Thanks in advance for any insight.