I use Helicopter scuff sheet from Bulldog, although would like to experiment on some fibre ones, as they don't add as much weight. Helicopter scuff sheets add anywhere between 12-16g, and toe guards add on 7-12g. There are 28g in an ounce, so essentially, you could have an ounce more wood instead of a scuff and a toe guard. Seeing as an ounce is enough to put people off buying a bat, the weight you can save by using a much lighter scuff and shoe goo instead (Around 2g for shoe goo toe guard) can actually help improve pick up marginally. Pros use them so they can have more wood behind the ball, and probably because they're so thin, that performance isn't really dampened at all.
I would say the best at protecting your bat are the Laver ones, as they are pretty thick, and I haven't found them to dampen performance that much really, although I've never tried a Laver without that scuff... If they do dampen performance, then L&W are certainly doing something right in their bat making, since my match stick is a Laver! (And I've had lots of bats pass through my hands)
For an expensive bat like the Carbine, use a clear scuff, so you can show off the grains.