I don't know much about Impact. I had only ever heard of them for the longest time (since I was a teenager), but never got my hands on a demo or saw them play since they had already disbanded at that point. All I do know, however, is that they were from California and played A LOT, according to show flyers I have seen with their name on them, and were a part of the spirit-filled hardcore entity with Focused and Unashamed and all that. It's very good stuff, even though it's extremely raw considering it's ripped from a cassette. The music is super good though, and I WISH it would have at least been digital tracks from a CD, but with old hardcore you take what you can get. I appreciated the hell out of old, shitty sounding hardcore music when I was young, and I still do! If you want to hear the one and only actually decent quality recording of Impact though, check out the Helpless Among Friends, Volume Two compilation here on the blog. Their song, "Within", is featured there. Give this entire demo a listen, definitely worth your time. I'm really surprised this band didn't get signed and put out with the same force behind them asFocused, Unashamed, Overcome, and other great Christian hardcore bands from that time did. My source who provided this rip for me may get around to doing the same for Impact's second demo (and final recording) which is called Striking Distance.
Here is an interview with Impact from a zine called Nothing Left. Pretty cool to read this.