Interesting question. Looking it up Mack Brown took over UNC in 1988 and went 1-10 that year and again in '89. The team showed improvement in their records each of the following years going 6-4-1, 7-4 and in 1992 9-3. They finished the season ranked from 1992 - '95.
Brewster came onto the staff in '88 as an unpaid volunteer and by '89 became the special teams coach/recruiting coordinator. According to Allen Wallace's rankings (full disclosure, I got this from a
husker board seems legit though) UNC had not been ranked in the top 25 in recruiting before 1989. In '89 UNC's class is ranked 15 and the next year 9th and 18th in 1991, 22nd in 1992 and out of the top 25 in 1993.
Drawing conclusions from this or comparisons to his recruiting at MN is a stretch. First of all, he was a recruiting coordinator there and is a coach here (where he still recruits but you would think does other things too.) Second North Carolina has a different player pool than MN. Etc. Etc.
It is interesting that Brewster had his best classes the first couple years Mack Brown was there while the team's record was improving. Arguably 1992 was the best year of the Mack Brown era, when they won the Peach Bowl and tied Georgia Tech (National Champs), but didn't seem to show huge benefits from it with Brewster's 'worst' class to date ranked 22. In 1993 UNC finished out of the top 25 in recruiting, but returned the following year.
Like I said I'm personally not drawing conclusions from this because there are too many variables but I wanted something else to do besides homework so I thought I'd look it up and share what I found.