i have been running 195/55R15 R1Rs on my s13 as thats what it came with. surprised how much grip they (HAD). they are getting quite fucked now. i guess they are worn out but as soon as they start to get a bit of heat in them they do hookup really well. if they whernt so expensive id buy them in 17". 595 RS maybe worth considering. only thing is apparently they need warming up before they have any grip which for drifiting isnt so great (street or track).
ill prob go with revspecs in 205/40r17 when i swap to 5 stud. not super grippy but should be enough hopefully. was also thinking about 595evo but the sizes in 17" it a bit ghey.