The Kouba links will drop your bike by about 1-1/8". If you don't need that much you can use these http://www.murphskits.com/vlinks.htm
, they will drop your bike by about 3/4". I raised my front fork by 20mm which dropped the bike by about another 1/4". I also shaved my 650 seat on the sides to make it more narrow.
As far as the bike sagging, It may sag a little as it gets older but not much. Also, make sure the seat you are looking at is actually lower than the stock 650 seat. I've seen some mention on this forum that the Suzuki -20mm seat that is made for the DL1000 is actually the same height as the stock 650 seat.
Some might also suggest that you turn the preload on the shock all the way down but I'm not a big fan of this method. Unless you are only using the bike on flat straight roads IMHO the rear shock should be adjusted to the proper sag (around 37-40mm) for your body wieght. If it is adjusted to soft it will allow the bike to pack down on hard curves which will make the bike want to run wide in the corners.
I ride my DL650 fairly hard and this setup works well for me, I do scrap the pegs occasionally but I tend to slide off the seat and lean my body into the turn which helps reduce the need to lean the bike too much. If I feel the need for a road burning run I pull out my trusting blue SV650S which has been retrofitted with a Penske/Traxxion Dynamics suspensions so she goes through curves like greased lighting.
One last thing, I'm not sure how much you have ridden or what kind of bikes you have owned in the past so I will make one more suggestion. Go buy the book "Sport Riding Techniques" http://www.amazon.com/gp/product/189...lance&n=283155
if you want to learn how to ride sport/sport touring type bikes harder and with more confidence. I came from riding Harley's for years and was suprised at how agile these bikes can be once you learn the proper techniques. Good luck and ride safe.