You need to use the subjunctive mood. The meaning of the sentence will change (as you require) if you use the subjunctive mood instead of the indicative. Present simple in the indicative mood: "I consider it very important that these signals ARE exactly the same." This means that they are the same. That is not what you mean. They are not the same. You should not use the indicative for this sentence. Present simple in the subjunctive mood: "I consider it very important that these signals BE exactly the same." This means that they are not the same, but you want them to be the same. That is your intended meaning. The verb "to be" in the present simple indicative: I am You are He / she / it is We are They are The verb "to be" in the present simple subjunctive: I be You be He / she / it be We be They be Not many people bother to study the subjunctive mood in English. Try to remember it. It's useful.

Hi, I consider it very important that these signals need to be exactly the same. is ok, but you're emphasizing need when you don't have to, so - I consider it very important that these signals are exactly the same. is a little simpler. Hope that answers your question :)