Having some problem to solve a the offset of my RST!

i got 17"7.5" 7 spoke diamond cut and when i turn the wheel they hit inside! (tire 205/40/r17) i already got some spacers (5mm)... but donīt know the ET number of the 7 spoke!

so i wonder if it can get 17" 8" ? will it hit? the offset for the new wheel are ET35 too! (compomotive MO17)...

http://www.1010tires.com/wheeloffsetcalculator.asp

iīve been calculating and if the original wheel of the RST are 15"6" and i want to put 17"8" it tells me:

-Inner Clearance: 25mm LESS (the inside of the wheel to the strut housing)

- Outer Position: EXTEND an extra 25mm (position of the outside edge of the wheel)

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whats this means? the new rimm goes outside or inside?

sorry the newbie question!

what kind off problems i will have?

ps: i still have the chance to buy the compomotive MO17 17"7" et35 to have no problems in hiting?

Hope someone can easily post a coment