I'm running 4x100 on my SS/TC so I can share wheels with my miatas... 15x9 is a good size anyways with amazing tire selection so I probably would have gone this route regardless of what wheels I already had on hand.
Base model hubs up front, and I redrilled my rear hubs on a bridgeport. I also redrilled the rear solstice rotors and front LSJ rotors to 4x100. Admittedly I didn't do research, but I vaguely recall that SS/SC shares the same splines with the N/A SS, so you can run 4x100 rear hubs. The SS/TC (I believe) has different axles, so this is off the table. Double check me here, because I never researched this, I just recall seeing it somewhere but I stopped researching because I was spending more time researching than just redrilling the hubs.
4x100 is the easiest pattern to redrill... you literally just need to indicate center, and then move 50mm out on each side in X and Y. If you don't have machine shop access, I'd bet a local machine shop would do it for a very reasonable price. FYI, one of your new 4x100 holes will intersect one of the old 5x110 holes.. there's no way to avoid it. I would recommend filling the lug hole that will overlap before machining the new holes; you would want to machine a press fit dowel to fill the hole, tac weld it into position away from where they have to drill, drill the hole, finish welding, grind down the weld. You don't want to fully weld the dowel beforehand and make the machinist suffer by making them drill through a hard weld. Alternatively, you can just drill the holes (which would give you more of a slot at the intersecting hole), bolt on a 4x100 wheel with the studs (the 4th stud that is in the "slot" will get located perfectly because the other 3 studs are on center), and TIG weld the backside of the stud to the hub. Ideally, you'll have a helper holding a wet rag on the other side to retain the temper on the stud. The temper on the shoulder of the stud (where you'd be welding) isn't very important.
