xAggerator

im a noob wen it comes to rims/tires(almost decided on never getting them if it wasnt for my dad >.<) and im planning on gettin 15" work equip's for my xa. ive read the faq sticky thread and i dont seem to find much info on xa's and rubbing issues and such (or im jes blind). but what size tires will fit 15x7.5f/15x8r equip's? will they rub and also how are offsets supposed to work actually? i found a site that does custom fitting equip's and i want to make it so i can hav the wheels as flush with the fenders as possible w/o rubbing(if thats even an issue) and as deep dish as possible. my car is dropped 1.8f/1.6r btw. thanks