confusing

hi. im going to drain the old coolant and fill with fresh...im looking at all these different pre mixed ones..are these ok...and which colour thanks for your help

Not sure on the pre mixed ones but our block and age of car requires blue. I won't argue with everyone like last time of the ins and outs as it can take a while for it to cause damage but it dose

I've always used premixed and had no problems. Your climate is very different over there so that would be a factor.

Iirc it has to be ethline glycol free

^that the main ingredient of all antifreeze.
ethylene glycol or propylene glycol (the green tree hugging hippy mummy choice) is the main ingredient for altering the freezing point.
main difference of the 6 base types of antifreeze is the corrosion inhibiting chemicals of the product.
you can use both IAT & OAT based products in the SR20, just don't mix them, buy quality product & change it at specified service times as the inhibitors get used up in time so must be changed to keep working effectively against corrosion.
OAT based antifreeze is not suitable for use when copper or brass is present, it also can have effects on plastics & seals but this is not the norm for quality product & more modern cars.
I've seen no problem with either IAT or OAT coolant products in a huge amount of 90's onward jap cars, both types used & recommended by specialists, motorsport/clubman/engine building  experts alike.
Don't rely on colour as that can vary due to some makes doing their own thing hence the blue which you see in bluecol & holt IAT antifreeze, IAT is normally green & green is what the nissan coolant was, Japanese tended to use more phosphate based anti corrosion while a lot of EU & US IAT antifreeze is more silica which not always a good thing. Also if mix your own use soft water or distilled rather than deionized ....

thanks for all the info..guys