I have an s13 with a ca18det swap in it. Im wondering if an sr20 clutch kit will fit the ca18? Also what type and stage of clutch would be best for drifting and street uses?
The clutch should, it’s the pressure plate that won’t.
I ran a KA clutch with a CA pressure plate on my CA-powered S12.
Nissan used very few different clutches (the center spline seems the same in most cases)
In any event, I have a 300lb-ft clutch and PP for a CA with less than 100km on it for sale. Motor went blow-uppy 
17psi, clutch never slipped … wish I could say the same for my headbolts!
You might want something more aggressive for drift competition though.
PM me for details if you’re interested, shipping shouldn’t be horrible.