yes Marki SR's are side feed too, same as RB25's...
S15 have like 470cc injectors, so it could be a cheap upgrade for an rb25, however when i was in the market it was hard to get a set of 6 as everyone wants to sell 4.
Plus for the money I was able to buy a set of 6 nismo 550cc units brand new, which was far more fitting to my application in the end...
BTW Do you have a name for that tint joint???