Greenspan's latest speech is a good defense of liberal trade policies. Unfortunately, he does not address externalities such as tax-base competition and environmental abuse, but it's still a good recap of the last 60 years of macroeconomic policies.
Compressed SLIP should outperform PPP, as PPP has 24 bits of packet overhead that C-SLIP doesn't have (minimal packet format). The should comes into play as the Van Jacobson and "other" compression algorithms should be the same compression ratios, and the modems should catch line noise-created errors. Granted, we're not talking huge differences, but why pick the slower? ;)