So physical supernatural manifestations of the Holy Spirit can only be seen by faith? Is that your point?
I eagerly await your non-answer.
The faith comes by hearing the word of God, such as, not forsaking the assembling of ourselves together, as the manner of some is; but exhorting one another; and so much more, as ye see the day approaching.( Hebrews 10:25)
The physical manifestation would be getting up Sunday morning, dressing, driving down to my church and faithfully participating as instructed in the word of God, week in and week out continuing faithfully. This is not something you find the natural man doing. Again, hearing the word; Study to show thyself approved unto God, a workman that needeth not to be ashamed, rightly dividing the word of truth. (2 Tim. 2:15) Physical manifestation of the Holy Spirit would be the desire instilled in me by the Holy Spirit and to act on what was written in His word, meaning, sit down open my bible and begin to study. The natural man has little to no desire to know the things of God.
I'm not completely sure what you mean by manifestation of the Holy Spirit, however, if your looking for some kind of mystical supernatural experience to validate your salvation you might be searching in the wrong area, simply put, read God's word, believe it and trust that what He says is true. A simple definition of faith, believe God at His word. Exactly what sort of conformation or proof other than God's word would you need or want?