The 19x10.5's won't fit in the rear unless you roll and pull the fenders, offset is too low. They stick out 1mm more than my wheels and I have a 255 tire and a roll/pull so unless you stretch the tire it will rub badly. The others are too high. Rico is right, the choices suck.
For reference, Connie's Cougar has 9.5's on the rear with 32mm offset. The only 9.5's listed are 42mm, which would pull the wheel in .4". It will still clear the brakes/suspension but will tuck slightly better. I like the look of Connie's wheels but it's a little aggressive compared to a "Euro" look. I think the 9.5's with a 275/35 would fit fine. OD is 26.6" which is stock.
On the front, her car has an 8" wheel with 20mm offset. It has basically exactly the same dish as the rears, and really fits about the same - just slightly out. If you want the fronts to tuck better, then the only thing you can do is run a narrower tire because the way the 8" 20mm sits is almost identical to how the 9 32mm sits. The 8 35mm is way too far in, the 8.5 20mm is further out than Connie's, and the 8.5 45mm is the same as the 8 35mm.
So you are really down to either 4 of the 9 32mm, or staggered with the 9.5 32's on the rear. Since your fenders are rolled, I think the extra offset in the rear will be fine.
Tires, 275/35 in the rear, the front 245/40 or 265/35. The 245's will be stretched to fit the 9" wheel a little, but that will help front tire well clearance so that may be a good thing. 265/35's would fit the wheel better, but will be just a touch shorter at 26.3"
If you want to go with 9's all around, then 265/35's all around also.
I think 18's look good on the car, but not really the "Euro" look, more like "American Muscle". 19's are definitely oddball. 20's are edgy which is why everyone is running them. Definitely a lot cheaper, but ride is a little rough and wheels are pretty heavy.
With the SVO motor, I'd do 18's and go more for the mean and nasty. The car is not going to ooze sophistication.
The look I would do on Toms car is if I may say is. Its not the Deep concave mesh look found on new Euro cars. It will look dated in a few years, just like his highschool 15" wheels he is rocking now.
If I was to spend decent mula on wheels, mind you I change my wheels often but I am cheap to buy them.
What I would spend it on, 19s like Tom intends, It would be a double lip barrel with a two piece look. Staggered. Deeper in the rear. Rivets or no rivets. Mesh or spoke or multi spoke. Thats a look that says you mean business on the streets. And looks good at the car shows. Its not really muscle like boyds look.
If not then some billet wheels similar like Dave N copied Billet/ machined wheels always look good and expensive.
Hella Flush Euro is hard to pull off and BBS style multispokes might be a mistake on this car. Although nobody has tried it, It would be a neat sight to see.
Micah has brought a new style to the SC world with his deep concave 20s but he has a lip so it gives it a muscular look while looking exotic. But it has a time stamp on it just like his old BBS, which looked great for a while then you can start to see its age. Similar to Dalkes wheels that he likes to swap around his fleet.
Some wheels are timeless. Saleen 5s Cobra Rs sure they are played out but dont really have a time stamp on it because they are simple in design. Although time will take its toll on all wheels.
Tom you should consider a doube lip barrel. Shanes car had it and although it had too much neg offset, it looked mean and cool.
Wow there is a lot of information to take in here. It is so much easier just to copy somebody else when it comes to wheel fitment. I really enjoy the mesh/multispoke look and I am not the first to do it. Duffy (thanks) posted up a photo years ago that is still with me today of the CarCraft/Bonneville Supercoupe. I'm going to check out this double lip barrel thing that Ricardo posted up.
20x10.5 (+45) = 3.95 front space, 7.55 backspace
20x9 (+36) = 3.56 front space, 6.44 backspace
Use my rears as a guide. You don't want it sticking out further - so that's what nearly a 4.0 inch front space looks like. And it looks better than it really is because my tire is stretched. If you go further than 4.0 fs in the rear, it'll be retarded, so the 10.5 inch rim is a dealbreaker. I think the 9.5 will fit pretty good, but now you gotta match the fronts to it. Keep in mind our front tracks are 1 inch wider than rear, so you want something about 1/2 inch less front space on the fronts in order to be even with the rear. That puts you at 3.11 front space - or the 19X8's.
19x10.5 (+27) = 4.67 front space, 6.83 backspace (retarded)
19X9.5 (+41) = 3.61 front space, 6.89 backspace (thumbs up)
19X9 (+32) = 3.72 front space, 6.28 backspace (retarded)
19X8.5 (+45) = 2.95 front space, 6.55 backspace (retarded)
19X8.5 (+20) = 3.95 front space, 5.55 backspace (retarded)
19X8 (+35) = 3.1 front space, 5.9 backspace (thumbs up)
If you want to double check the math (to keep me honest), figuring this all out is pretty easy. Every rim's advertised width is REALLY 1 inch wider because they don't account for 1/2 inch at the front and back of the rim for the bead. So the true centerline of a 10 inch wide rim isn't 5 inches, but 5.5 (11/2). Once you know the centerline, you can figure out the rest from offset. +45 for instance is divided by 25 to convert to inches. +45 = +1.8 inches. On a 10 inch rim, you start at the 5.5 centerline (remember, it's really 11 wide) and add 1.8 to see 7.3 total backspace. Front space is just subtracted from the width (again, not 10 inches, but REALLY 11.) So 11-7.3 is 3.7 front space.
The key is if you know how an existing set of rims already fits on a vehicle, then you don't have to visualize. Like with my car you can see how much 3.95 front space is in the rear, and how much 3.56 front space is up front. So those 19's I selected earlier would sit about 3/8-1/2 inch further inward. Which is a good thing IMO, cause then you can run a tire with a little buldge and still have it fit within the wheelwells.