I think it is funny how people think they are buying LMAFs calibrated for 42s. Most aren't. They just happen to be a curve that at the top-end of the curve matches well with the capabilities of 42s. But the lower end of the curve doesn't match up well at all with what a real "calibrated" MAF for 42s looks like. Although I guess it is possible there's some company out there that can recal these things. But I suspect people are just selling LMAFs with 42s as matched sets when they really aren't.
As for the LMAF, if it is the same sensor as the stock sensor, they don't work well in blow-thru setups. So unless the MAF is installed in a draw-thru configuration, you'll want to upgrade now. And no, I would not recommend an upgrade to a C&L. Go with something a bit higher quality than that. I think another thread here recently in the last day or two was recommending an 05 slot style MAF over the LMAF for blow-thru configurations.
89 Ranger Supercab, 331 w/GT40p heads, ported Explorer lower, Crane Powermax 2020 cam, 1.6RRs, FMS Explorer (GT40p) headers, Slot Style MAF, aftermarket T5 'Z-Spec', 8.8" rear w/3.27s, Powertrax Locker, Innovate LC-1, GUFB, Moates QuarterHorse tuned using BE&EA