125-200cc '99-'00+ 125 parts interchangability

I just purchased a 99 WR 125 which will be a bit of a project as it needs some TLC. So far I've amassed a list of things to replace including levers, shift lever, plastics, and seat cover. My last project like this was my 99 KTM 380 (don't hate the pumpkin!) which I converted to '07 bodywork along with powdercoated frame and swingarm. I'd like to do something similar with this bike. It appears that it may be possible to upgrade to the 04 bodywork for increased choice and availability of graphics by swapping on tank, subframe, airbox and seat. Is this correct?
How about the other things like the pegs, levers, and shift lever? I've found aftermarket parts but it's mostly listed for the newer bikes. I've searched the forums but haven't found a whole lot on the older bikes. Oh ya--I'll post some pictures soon and track the project for you guys.
Thanks!
Jason

Short and easy answer is yes. Ive got a 98 125 which is now wearing 2005 plastics using the parts you have listed. Ive also fitted a HGS pipe from a 2002 bike but the silencer needs a bracket made to fit but i will be fitting a new silencer for a 00-05 model.

Thanks for the reply, Parfo. The newer the better. Is the most modern I can go 2005? I planned to go to the 2000-2004 stuff but if I can use the next generation that would be even better! I think I'll either go with red and white or blue and white if I can still find the parts.

It is essentially the same bike thru 2008....bodywork may require some fabrication but nothing major.

I went for 05 as I came across the parts to do it but like R_Little said, you can go for the 08 stuff too.