A good laptop can handle both UAD and Waves (only not too many instances of them(with UAD only one card)). So if you want to work with a laptop, instead of a desktop, you can do it.
"Will it lead to crappiness?" Yes, if you think that everything going through Digi002 comes out as crap. Otherwise no. An AD/DA conversion will always degrade the sound. If you're not happy with the 002, try RME, Apogee, Lynx, Lavry or Benchmark instead.
There are plenty of good compressors for the 500-series. Try a few and buy the one(s) you liked.
Good luck
