What can I do to get neater prints? (Photos included)

[Sloyfa]

I'm using a Makerbot Replicator 2. I have several, and several years experience printing. The printers have no upgrades, are all identical, and my filament is Makerbot branded PLA and I use Makerbot Print or Makerbot Desktop (on different computers).

The problems with the prints are consistent across each of the (3+) different printers.

I originally wanted to print these parts to make cast molds from, but am surprised by the quality of the plastic of the print, and would now like to clean up the print and use actual prints as parts (just in a different color). They are truck rims that fit small realistic tires, and the file I have to print is nearly perfect, except:

1) it seems something is wrong, you can see the small circle that was made in the software to create the hole, but it seems there's gaps around that inserted shape. Is this from the printer/filament, or is this a problem with the file? How can I fix it?

2) The whole thing prints with an amazingly perfect surface (for what I need) but the underside of the top and edges have curly stray strands. I know supports are the normal solution for this, but when I tried supports they made even more of a mess (overall) to the finish of the print, and the "overhang" is very little, so if there is ANY alternative to supports I can try, I'd want to try them.

3) On round edges, many times the "print" goes in a straight line and cuts corners. You can see an example of this in the last photo, but it's not the best example. Most cases have many of these straight lines where they are supposed to be following rounded corners.

For all three problems I've experimented with smaller print layers, I increased and decreased the temperature for different prints, slowed the print speed, and even went into the old Makerbot Desktop thing I had on an old computer and selected the "high quality" settings. In all cases the expected changes and smoother prints came out, but with the same gap around inserted shapes and under the overhangs.

I've also tried supports for the overhangs, but they ruin the surface smoothness and create more imperfections than they solve. I'd have the perfect printed part if I could clean up those squirlies on the underside of the edges, if anyone has any suggestions what I can do to fix them, I'd be glad to hear from you.

Also, I don't mind spending money, time, or effort if there's a solution. I don't mind printing slower, using more filament, whatever the downside, in most cases it won't matter to me.

I'm adding some photos so you can see what my part is, and the problem in the print that I'm having.

Thanks in advance for your input!