I tried to test fit gen2(36 offset) 15x8 949s with 205/50-15 Nitto NT-01 tires on a classic B13,with RM/AGX .Rear fenders rolled.
With a 5mm spacer on the rear,the clearance was like a sheet of paper between the sidewall and the strut body at rest (1mm at the most).I am pretty sure it would rub around corners with any tire flex.
Perch was no problem in the rear with the 5mm spacer.
Front was ok with no spacer.
I lost the pics I took...not sure where they went or I would post them.
With a stock type strut,The 15x7 may work good,but you need coilovers to run the 15x8.