18x9 03-04 cobra 5 lug swap...

title says it all, i have a set of 03-04 cobras, all four 18x9. i know nothing about wheels and the 5 lug swap so i was wondering if someone could help me out.

5-lug (5X4½). All four rims are 18" x 9", +26mm offset (6.11backspace)

thats all i know about the rims, now can someone help me out with the parts i need to make these wheels fit, and any tire size suggestions would be great too. (im thinking 245s up front and 275s out back, right or wrong?) im planning on throwing on some eibachs while i have everything apart, a 1.25 inch drop shouldnt be too much of a headache right?

also any problems i may run into, if you could lemme know what im in for i'd appreciate that too. I finally have the wheels and the money for tires and 5 lug swap, help me out.

and for the people who tell me to do a search: i still am completely ignorant about wheels and fitment ect, so anything i read goes over my head.

thanks in advance guys.

that sites not workin, thanks for the input. im not trying to be a pain but i really have no idea what i need. if someone has had this same set-up and could gimme a list of parts, you have no idea what a help you'd be. any other comments/help?