Does "ripping" quality improve if you.........

yes, Edesilva, so far all my CDs play. I can't say what'll happen in the future. maybe being a vinyl guy helps?

Edesilva,
"Actually, I was talking about CDs bought off the shelf. I've got several CDs that won't play in my DV50s, my Theta David, or my Sony."

Now, this is interesting! I've never had this happen to me w/ CD originals bought off the shelf! And, my CD players are very much older than your DV50 - my Harmon/Kardon CDP is 11 yrs old & my Wadia 861 is circa 1998. They both read every single original CD & CD-R that I've thrown at it. I have 1 CD-RW that the Wadia will not read but I expected that. I haven't tried this CD-RW in the H/K but I sort-of expect similar results as the Wadia.

I agree w/ Kjg when he says "...it isn't likely that the tweaks you mentioned will have any impact on the ripped files" but for a different reason (not "My best guess would be that because of the advantages of the ripping process...").
I had a discussion with Guido Tent (of the Tent XO Superclock module fame) & also read some articles. The consensus seems to be that even a cheap CDP transport (like the $35 Magnavox DVD player at Walmart) reads CD data with virtually zero errors. The manuf seem to get this part nearly 100% correct. So, when you are ripping CDs, it's merely data extraction & it is nearly always correct. If you use free-ware Exact Audio Copy (like Kjg suggested), it has an in-built routine to check the ripped data vs. what's on the disk to ensure what was ripped is an exact copy.

The tweaks that you mentioned are (very) important when it comes to playback using a 1-box or 2-box CD playback system. Anti-static treatment, green pen on the edges, using a blade cutter to smoothen the outer edge, black fill around the center hole, using Herbie's mat, using black CD-Rs are tweaks that are designed to reduce the laser reflection off the CD during read thereby making the laser drive mechanizm work less hard so that there are fewer voltage & current spikes drawn by the drive from the power supply unit. This, in turn, has the effect of inducing less jitter on the clock ref, which is generated in the CD drive in cheap units. This, in turn, xlates to more predictable data fed into the DAC, which is extremely sensitive to power supply fluctuations & this yields reproduced music w/ less digital glare. A very simplistic overall view, which quickly highlights some of the central issues of why these tweaks work (when they do).
FWIW. IMHO.

Edesilva,
"Virtually everyone has had CDs that are unreadable or skip in even high end transports."
yes, I can believe this. However, I do not believe that this is an error during data read (which is what I wrote in my post. An error during data read implies that the transport recognized the CD/CD-R/CD-RW, etc & is able to read the recorded data). What you are pointing out is a disk recognition error. Indeed, it is true that certain consumer CD transports will not read certain CD-Rs & CD-RWs while a computer (CD-ROM) drive will routinely read such disks.
What I implied in my original post was: once the transport recognizes the disk & commences reading the recorded data, the errors during read are virtually zero for even el-cheapo transports.
Hope that this clarifies.