The 250R does have a real soft suspension both front and rear. I have had the same nose dive problems you talked about. With the rear, you can swap out an EX500 shock and it will bolt right up. The front, you can use the EX500 front springs to make the front suspension more solid. Or, there are race springs available too.

The Yamaha mirror has one main problem. They have two studs that stick out, but they really aren't long enough to get a nut on them going through the factory brackets. What I did instead was make a backing plate out of metal for each mirror, so the mirrors are now directly mounted to the fairings. Use the thinest 6mm nut you can find for mounting the mirrors along with some blue locktight. Once you bolt up the main fairing again, the fit becomes a lot tighter (Note: Original mirrors are mounted THROUGH the fairings, and onto a bracket.) You'll see what I mean once you unbolt yours. It was also necessary to loosen up the upper fairing piece to get behind the fairing. You do not have to take it off, just remove the mounting bolts so you can work with it. There is also a hole size difference between the R6 mirror studs and the holes in the fairing for the original mirrors. go to your hardware store and see if you can find some sort of bushing to keep the R6 mirrors centered.

And yeah, asiancycle is where I got my turn signals from. They are the best you can get for your bike. I'm very happy with mine.