Without seeing exactly what you're trying to duplicate, it's hard to say, but a Day-Glo type of effect definitely requires spot color, and you're probably not going to get what you want without one.
That said, try exporting your PDF/X-1a with a GRACOL color profile or (way better) ask your printer for a .joboptions file specific to his press and the type of paper you will run on, add it to your PDF presets and use that. David mentioned GRACOL and how antiquated SWOP is in IDS podcast 91.
InDesign defaults to SWOP for CMYK export to PDF, and that's often (usually, in fact) not the color profile you want because it's intended for web presses, not the sheetfed workflow that's much more common. You might be quite startled by the difference.
SWOP isn't a good choice for web press jobs either, in many cases. Magazines with any kind of decent regional, never mind national circulation are always done on a web press, but when I prep an ad I always use that publication's .joboptions (from their print provider), never the InDesign/Creative Suite default.