NOS ha ha ha


1 sorry but the short answer is no
2 t3/t4 are great! they come in so many different trims its not even funny you can even get a ball bearing upgrade for them now..... but ebay turbo's (ie xspower-ssautochrome) arent so hot their cheaply made and have been known to blow and cause serious damage to motors - imo if i were you i wouldnt use it
3 Je pistons are good and will most likely suit your needs
4 a .20mm overbore is a oversized piston. if you have a b18c1 you have a 81mm bore that means if you oderered those pistons for this motor it would be 81.20mm (not half) these pistons would only work if you had your motor bored over

hope that helps