Re: Ea 1991
XC onwards WILL fit, not that anything other than ghias or GT would be any better than you have(PRE XC had a small centre bore and XK etc had 4stud)
a set of XE ghia wheels etc are a standard look 15"
EF steel wheels painted silver look good 15"
ANY XR6/XR8 wheel would look good
make sures you get nuts with whatever you buy(they can be dearer than the wheels)