Hi!
I plan to buy sonar platinum as an upgrade from sonar 8.5 producer.
I installed win7 from scratch because I switched to an ssd and I had some software issues in the last install.
My question is: should I also install sonar 8.5 to get all its plugins and instruments or is it everything already present in sonar platinum?
Thanks!

Hi. From 8.5, I believe that only Lexicon Pantheon is not included in Platinum. You could get this with an advanced install of 8.5, and only choose the Lexicon.
All the best.

Yes install 8.5 ( 64 bit version) first and set it up with your preferences. Things have changed  a LOT- and it will speed up the transition if you get 8.5 the way you like it then install the new version. You're used to 8.5 so it will be easier to set it up.  It will ask if you wish to transfer your preferences over from 8.5  during the install of Platinum so say yes. 
 
There's a bunch of stuff that came with 8.5 that is not included with Platinum. And you might want to open older projects in 8.5 until you learn the new software. Give yourself lots of time and hair pulling as they have really made a mess of the way things used to work starting with X1. It is better once you get the hang of it.  
 
On new builds now I install 8.5 but use the custom option and I pick what extra stuff I need and leave outdated stuff behind. 

thanks!
so i'll install 8.5 first... 

I'm with Ken on this one - the only thing I install from 8.5 is Lexicon Pantheon as an advanced install, though there is certainly no harm in installing the entire program. My theory is the more time you spend on Platinum the faster you will discover it's advantages and grow to love it. I guess I'm a deep end kind of guy:)

I had problems with X1 + X3 that were show stoppers, so I was stuck using 8.5 until Platinum. Fortunately Noel fixed that last remaining things in Platinum for me that were show stoppers, so I went to Platinum about 15 months ago. I love it now, but it'll take some time to adjust. For sure install 8.5 first and get it working right. Take your time with the transition and you'll be fine.
 
You really need to upgrade to Win 10 before the free period runs out next month. If you don't like it for some reason, you can still use Win 7. Read my post about Win 10 upgrade and you'll see why it's a no lose proposition.

I think besides Pantheon,  V-vocal,  GuitarRig Le and Rupture Le  LE are not included in Platinum. As long as you installed 8.5, V- vocal is installed automatically. The rest are from advanced install. I am sure if Perfect Space is included in Platinum. Someone correct me if I am wrong.
I would recommend Groove3.com videos on Sonar Platinum to get you up to speed. Check somewhere in the deal forum for a free one month code.

Rupture 

A stripped down install of older Sonars takes up very little room , just don't install any of the extra stuff after choosing Custom. For me it was True Piano's because I only had X3 Studio. Now I get True Piano's with Platinum so I won't really need 8.5 next build.