I went for a 120km ride this afternoon. I'm 180lbs. Back suspension is a bit soft and springy...but I must say roads around here are TERRIBLE. It might be a bit too soft for when I have a passenger (havent tried yet), but otherwise, it's a pretty decent balance between confort and performance. If your roads are nice and smooth, you might want to replace the rear shock and possibly the front fork too (if not just change oil density in the fork) to make the bike feel stiffer.
But for real world riding, I think the shocks do a pretty decent job. Any bike can get suspension improvements, it just depends on what you do.
I only have 400km on the bike this week so I'm not riding as aggressive as I usually would (in the appropriate places of course and without traffic..), but I must say the handling is really amazing. As I've said in another post, it handles better then my 2009 Speed Triple which had far superior suspensions and handled great! Sure the rear bounces a bit, but you can flick the bike from side to side like a bicycle and it turns on a dime too. Always keep in mind these reviews are done by guys that the week before might have tried the R1 or MV F4...so of course you notice when you drop to a budget suspension. But it still does a great job. You can't expect full Ohlin suspensions on a bike this price. Unless you weigh 200lbs+ I really don't think a suspension upgrade is a necessity. I personally changed the tires to Michelin Pilot Road 2, that will certainly help in the corners. Even with the best suspensions, the tires will most likely be the first limit...
Put a few hundred km on the bike before you shop for new suspensions. As you might just feel they are perfect for your type of riding.