Hi 4SilverBullet6,
Since you've already made determination that these 2 NSR, full VCT-compliant camshaft grinds are what you're interested in going with, so deciding between the 2, IMHO I'd go w\ the Brenspeed Detroit Rockers cams vs the Howard's Rattler cams (even though they're more expensive) due to the overall HP\TQ output potential across the board (DR's have a higher dynamic compression curve than the HR's thus better TQ output potential) being much better from a tuning perspective..........sound-wise they'll sound kinda similar in lope cadence to each other at idle.
I've modeled both of these camshafts grinds & compared between them for a future NA stroker build of mine (using the OEM base 9.8:1 static compression as reference.......DR @ 8.967:1 dynamic vs HR @ 8.101:1 dynamic.......OEM cams @ 8.688:1 dynamic for reference).
There are a few YouTube videos of folks recording the idle sound after installing DR cams as well as HR cams using very similar exhaust setups (LTH's, high flow catted midpipes & Pypes Super Bomb exhausts if you want to hear the exhaust notes for comparison:
Detroit Rockers
Howards Rattlers
Hope this helps.