Plays on various "collectors," a PASSPORT collecting stamps, the GUINNESS BOOK collecting records, a CASH REGISTER collecting bills, and a PASTA BAR collecting shells. GUINNESS BOOK worked great for me, as it played upon two fairly different senses of the word "record." CASH REGISTER was also good since a cash bill and a "you owe me X" bill are different enough for my taste.

The others weren't as strong for me since some countries put actual stamps in your PASSPORT instead of just stamping it with ink. Yes, these aren't exactly the same, since you can't mail a letter with that type of stamp, but I like more wordplay rather than less. And the idea of a PASTA BAR "collecting" shells ... that was too tortured for my taste.
C.C.'s bonus fill shines, as usual — I give her a STANDING O in this regard. Along with MISS TEEN USA, MAD DASH, POINT GUARDS, BITTER END, there's so, so, so much goodness packed in. Note how C.C. so carefully spreads out her bonus fill across the puzzle's columns and alternates them up and down for good spacing — this is a great methodology for being able to incorporate a ton of snazzy fill.
With just four themers, all constructors should aim for this much great long fill. It's very doable any time you have four themers that aren't grid-spanning. Doable, meaning without a lot of crossword glue, that is. I did pick up a bit of ITAL, ISO, RTE, UNOS, but that was all so minor. Nice craftsmanship.
There was so much good stuff, I think it would have been passable if C.C. had put a black square at the E of PULSE, breaking up BITTER END, or a black square at the A of PISA, breaking up POINT GUARDS. I'm glad she didn't, since I so much appreciate all the great fill, but for more novice constructors studying C.C.'s execution today, both would be viable options that would make those tricky NW/SE sections easier to fill.
I would have liked the same level of a-ha moment I got from GUINNESS BOOK being a "record collector" from all four themers, but overall, C.C.'s strong execution kept me engaged throughout my solve.