18" vs. 19" wheels

[goldsax]

thanks for the replies..
its and SE spec.
looking at the 2006 brochure, 2 options

1) 8.5J x 18 ‘5-arm’ design high-gloss alloy wheels
with 255/45 R18 Y tyres

2) 8J X 18 ‘9 spoke’
with 235/50 R18 Y tyres

what ET would i need?

i presume the second option would be the most comfy...any disadvantages?
i bought the 4.2 due to its power/torque, would it be wasted with 235 tyres? at which point the 255 may be considered?
thanks again for the input..
raj