How did you import the images? Did you use File>Place?
When saving the .ai file did you tick the option for a PDF compatible file, in ILlustrator?
How does the image look when you print it - or when you make a PDF from InDesign?
I had this experience with a customer file today: the file is 72" x 48", placed into InDesign at 100%. Even at High Quality Display, it looked pixelated. However, when I zoomed in sufficiently, the display was fine. The export to PDF was fine, too. I suspect that there's a limit to what InDesign can display at that size, although I don't recall seeing that documented. Did an exported PDF look OK? If so, you're good to go. Let me know...
I tried exporting it to PDF. It does look okay, but only okay.
The text that was from the original drawing doesn't look that great (slightly pixelated). In general, the image just doesn't look very graphic, despite being an interesting design. There just seems to be a slightly halo (maybe one or two pixel big) around all the lines.
Any way to clean this up?
PS on another note - is there a way to increase line weights in illustrator? I remember someone telling me this was possible...
Could it be that transparency effects are applied in Illustrator? If so try to move all text in layers above.
You can select lines and enlarge their width in Illustrator. I would use Graphic Styles and change it globally with them in Illustrator.
How would I be able to check this? I haven't done anything to the IA files, just crop/save it.
If you like, send me the files (original AutoCAD, your Illustrator file, your InDesign file) and I'll take a look. claudia [at] practicalia.net