Do the MY98 standard wheels fit an MY95 with no modifications or are they a different offset setting???

Same fit.

I put them on my 96. They transformed the car, looks and handling.

The offset on the 15" wheels is 55mm
on the 16 x7 wheel fitted to 98 MY it is 53mm
The ride is a lot harder with the 16" but the handling is sharper.
Some say you can acheive more by fitting Bridgestone SO2 tyres to your 15" rims and with no deterioration in ride comfort. The SO 2 tyres are much better, quieter and more comfortable than the standard Bridgestone RE71 on the 15" or RE010 on the 16"

So, whats a boy to do?
Spend a few bob on damn good tyres and blast the existing wheel gold, or spend a few more bob on some beautiful gold wheels and damn good tyres?
(I prefer option 1)

It depends on how much money you want to spend.

I will admit though I would probably go for the 16 inch wheel option, as I personally have never like the style of the 15 inch wheels, even when they are "goldenised".

When I brought MY 96 the previos owner had 17's on it, he part x'd it for a S reg took the stardard 16's of it, put it on mine, and vice versa. I've had no problems, just ganna get them 'golded' now.