I'm assuming these people saying toshi's are overkill have never tried toshi's. They are probably my favorite thing that I've ever upgraded, or the most noticeable at least.
I have this exact same setup except sylvans instead of gr-9s and I really like it. I think my sambas are 11.5 and I run XL. they say large is for 8-10 and xl is for 10 and up, so you're kind of on the border. I'd probably go L if I were you.
anyways, I like mks clips but I'm switching to these shortly...
