I've always used the 165 section tyres on my 4/4 and IMO the standard Continental CT22 (The 'van' tyres that Catchpole was referring to) are more than a bit pants.
Vredestein Sprint Classics are, on the other hand, flippin' brilliant and can easily cope with the 165bhp of my car. I think T-Tracs have the same compound but a more modern tread pattern, and by all reports they are very good too.
I see absolutely no benefit to switching to wider tyres on a car with a standard engine. Change tyres by all means, but be wary that wider tyres do not mean better handling, and as the standard widths are easily capable of dealing with a standard 4/4 you won't improve grip either unless you drive like an absolute mentalist.
If you are looking to improve handling (rather than roadholding) then I think you'd be better focused on improving the suspension rather than widening the tyres.
If, on the other hand, you fancy going wider for cosmetic reasons then by all means fill your boots, but don't expect your car to feel 'better'. It'll certainly feel different, but you may or may not like the difference.
