Old picture of my "trail bike".
I wanted MX handling - so I fitted RMZ front and rear ends - revalved/resprung.
I wanted reliability and easily obtainable spares - so I stuck with Suzuki genuine parts for the build.
I used the 650 as the basis because it is well suited to open fast fire trails.
For 2 up trail and dirt road riding I put an RMZ front end onto the BMW using Emig Racing custom Triple clamps. The Ohlins has had substantial work and runs the heaviest rear spring I can buy for one (about 24kg/mm).
Rides like a proper dirt bike, which negates many of the less friendly aspects of a bigger bike off road. Actually a great deal of fun off road when solo.
Don't be afraid to experiment. No one will sell an off the shelf solution for your riding needs. Modification - that's the name of the game.
That's half the fun of riding.