18s will be fine on your car w/out any mods to suspension or brakes and i would go no less than 275s

 

Nobody makes a 240 wide tire so the discount guy is wrong unless you mixed up and meant 245/40/18. That would be smaller than stock.

Your two real options are: 255/45/18 all around or 275/40/18 all around. The 275 will be slightly smaller but not drastic. 285/40/18 is too wide for a 9 inch wide rim, not saying you can't squeeze it on there but I wouldn't do it.

No offense but if you put a taller tire on your V6, it will slow it down, not what you want.

 

+1 I was waiting for someone to say wtf on the 240's

for the V6 I would go 255/45/18. you keep the stock diamter, but get a wider footprint.
275/40/18 if you plan on dropping it, because you will create more wheel well gap as mentioned.

 

With the 275/40/18 the tire is shorter than stock and wider than stock. You don't want that because the wideness makes them look even shorter.

 

I will not be droping it so 255 all around would be good. Thanks guys.

 

Here's a cheap GT suspension:
http://www.stangsuspension.com/store...idproduct=1487
That's a good deal on my opinion at least, not unless you want something better.
As for tires I'd go with 275/40/18. With that profile 275 is the widest you can go with a 9 inch rim

 

Sorry stupid question but is the gt suspension better than the one I have? If so how? Thanks.

 

I'm pretty sure he meant 245/40-18 or 245/45-18.

The 245/40-18 is about an inch and a quarter shorter than your OE tire and is also at least 4 or 5 load indexes smaller load capacity. It could easily be overloaded relative to its capacity withoutthrowing a TPMS light. Not recommended.

The 245/45-18 is only about 3/8" shorter than the 255/45-18 and the OE 235/55-17 and 235/50-18 tires (all at about 27"). Half of that is reduced ground clearance and half is additional wheel to fender gap. That small amount might not be particularly noticeable to some, but might be to others. It's still a little smaller in terms of load index, but you might be able to make up the difference with a couple extra psi inflation pressure (haven't run any calcs yet). Your call.

The GT suspension is slightly firmer, and the car will roll slightly less in any given corner. If you're not too much into hard cornering, it's a pretty good suggestion for this wheel/tire combination just to keep the tire a little closer to upright in the turns and make the wear a little more even across the tread. If you are intending to really upgrade the cornering capabilities there are much more effective options (at higher price points). You can find a number of suspension upgrade discussions in the 4.6L Handling forum.


Norm

 

^^^ What he said.