245 in front is a tight fit and you have to almost nail it just right. I would think the 38 offset is pretty good, it's certainly not way off, but my guess is that you are just barely too far out. A 235 fits well for most folks and can handle a small range of offsets and still not rub. A little extra camber might do the trick as well. I'd guess you are rubbing on the outside of the tire - can you tell for sure (i.e. look for wear)?
The 38 offset is a bit much for the back, positions the wheels out farther than normal. Spacers wouldn't help just hurt. If you're only rubbing occasionally then yes the narrower tire would probably do it.
Thsi might help:
https://support.apexraceparts.com/hc...-Fitment-Guide