Wheel Size 18" or 19"??

OK, I`m considering a new car, an XK8.
One of the few options are wheel/tire "upgrades" The stock items are 18" wheels, the options are 19"
My question is would the 19" get me anything but looks? Any performance or ride pluses or minuses?
Frankly, I like the looks of the 18" wheel more.

improved handling compared with higher profile rubber Disadvantages: more expen$ive, PITA to parallel park, handling improvements may be marginal at best.

Stick with the 18", believe me ride quality is far more important than the marginal benefits you MAY get in the handling department. Big wheels with spray-on rubber are purely for looks and only work on ultra smooth bitumen. Anything else and you will regret it - your kidneys definitely will hate you!
Bill from OZ XJ Sport

After all, if going up 1" in diameter is automatically bad for ride and doesn`t help handling, then by the same token, going down 1" must improve the ride with only "maybe" a "marginal" detriment to handling.
But why stop there? Let`s *improve* the ride still more for only slightly (*maybe*, mind!) more degraded handling! Put on 16" rims... or 15"!
Since you don`t know which vehicle is involved, what the other factors affecting ride and handling quality are (chiefly, unsprung weight of the two different wheel/tire combinations), don`t you think it`s a little presumptious to just declare that 18" is some sort of magic maxima for the ride/handling trade-off?

wheels would offer a worse tradeoff and tacitly (by omission) that the OP doesn`t want to switch down to 17" wheels. irrelevant.

He is considering an XK8. If he wants a reasonable ride he shouldn`t consider anything above his standard wheel diameter. I am not being presumptuous! Having owned a number of Jaguars and Daimlers (I live in Australia) I think I have a modicum of knowledge about these cars. I also have the services of a tyre and wheel manufacturer at my service. This gentleman probably knows more about tyre and wheel combniation for various vehicles than you or I will in a number of lifetimes. One thing I do know, Jaguar puts the increased diameter options on its lists because there is a demand for these. However, increased diameter wheels with lower profiles tyres WILL result in detrimental ride qualities and not always a better handling response. Since most road surfaces are not exactly smooth as glass, ie; there will be lots of indentations and bumps, I can positively guarantee you will have a worse ride on a greater diameter wheel and lower profile rubber (with the same rolling diameter as the original). Whilst I will accept that the greater diameter wheel may well present a more aesthetic look, the real test is in whether the car is comfortable over all conditions. After all why is one buying the bloody thing, for looks of for good compfortable cruising over a long period. You do not buy an XK8 or fro that matter any XJ or XK series Jaguar lightly! cheers
Bill From OZ
JX Sport