Modern Vintage. In many Roadracing organizations (sans the CMRRA) 10-years old or older is considered vintage for racing purposes.
I think $2500 would be good for a clean bike with factory paint. But, repainted, this is more like a $1500 - $1800 bike. Period "mods"? They must mean the aftermarket filters on the stock CV carbs. Likely has an aftermarket pipe and is jetted. I see exactly nothing else in that pic that is modded. I guess the LP headlight bubble can be considered an "addition", but not a modification.
That being said, it looks a hell of a lot better than many I have seen lately.
Oh, BTW, stay away from the "850" big bore kit. That mod just made that motor very unreliable. 771 overbore is standard for that motor. This one has swapped parts to get the 850 size. If you break it, it will cost a lot of time and money to fix.
- Nut