What's the best spacers size.
 

I have some Varrstoen Es2 19x9.5 +35 but want to know what would be the best spacer size i was thinking 25mm in back and 20 MM in front Any suggestions?

Depends a lot on how low you are, whether you have rolled fenders, and what camber you run.

If you are stock height at factory camber you should be fine. Best way to figure this out though is to simply put the wheels on the car and measure the gap with a micrometer since it fits into that gap nicely. Then you know EXACTLY what kind of room you have to work with, subtract 5mm for a tight fit with little clearance. 10mm will give you plenty of room.

Make sure to take measurements with the wheels straight as well as turned to each steering lock left/right.

It's a little more difficult on an OEM height suspension because the suspension needs to travel down a bit to get a good accurate measurement. If you have access to a rack you can use a ratcheting strap to simulate suspension travel, or just guess. If your car is lowered then it's a piece of cake since it's already settled down.

If you don't have access to a rack then you can use a straight edge (anything that's about the size of the wheels+tires) and lay it across the face of the tire then measure off of that and just guess where the suspension will travel to.