It all depends on which classic-era kits you are interested in. The 1930s Fords, Chevs, and Plymouths, aren't too bad, though they are curbside (with the exception of the Plymouth, which has an engine), and have no chrome. The luxury cars and brass-era cars are nicely detailed, have plated parts and engine detail. IIRC, the only kit which wasn't that great, appearance-wise, was the 1952 Chevrolet.
The Rolls Royce was first issued back in the late 60's as part of Monogram's classic car series, while the Model A was first issued as a 6 in 1 kit back in the early 60's, with all the rod and custom stuff deleted years ago (along with the Cabriolet option). I can't remember any issues with the Rolls, but the roof on the Coupe can be a bit fiddly to glue; using CA and liquid glue would help.
If you want to go a bit more old school for superbikes, MPC had a Honda CB750 chopper in their old Monte Carlo kits. Not as exciting as a new suberbike engine, but probably a bit more racy looking than stock.
The S600 is a very nice looking kit, and Tamiya has made the appropriate revisions. One nice feature, not mentioned on the instructions, is the inclusion of the raised soft top, in additon to the hardtop and the boot.
Since I couldn't find Tamiya's ABS cement locally, I went with Chuck's suggestion and bought some Plastruct Bondene. It works great on the kit plastic. One warning to builders about the ABS-once it's bonded, it doesn't want to let go. I messed up on the location of the rear shocks (parts A4 and A5), and mounted them so the arms were parallel to the end of the chassis. Doing this caused a fit issue when installing the rear axle assembly. Go by the drawing in the instructions, and it will work.
As for the ABS plastic, I wonder if Toyota may be considering putting these out as dealer promos. Mold the body and frame in black, and assemble them at their plant in the Phillipines, and you would have a desk ornament strong enough to handle the occasional snatch and smash from a customer's kid. Just a thought.
Just picked mine up today at the LHS. One interesting feature of the kit is that the body and interior trees are molded in polystyrene, while the chassis and chrome trees are molded in ABS. I'm sure Tamiya had a good reason for engineering it this way, but it's inconvenient- I wanted to start building it, and now need to purchase some cement for ABS plastic.
The protruding headlights are the result of AMT/Ertl reworking the tooling back to stock in the mid-1980's (it had been changed into a Modified Stocker, with blanked-out headlights, back in the early '70s). I agree with the other posters; the Modelhaus bumpers are the best way to go.
There used to be a stock-bodied 510 4-door available from Hasegawa many years ago. I had considered grafting the wheel arches from this kit onto the Revell version for a stock two-door, but never went through with it. I had also considered dumping the Revell chassis underneath the Hasegawa body, but I would have had to extend the wheelbase for the conversion to work. Oh, well...
I have just started my build of the early Pantera (kit #RS-68). It's a simple build, but there are a few things to watch out for:
1. Those hood vents (cribbed right off a Mercedes C-111) didn't show up until later versions. It took a few rounds of filling and block sanding to get things level. The next coat of primer should have everything hidden.
2. The front and rear pans have the seams set up for the matt black on the later GTS versions. For an early car, there are seams very close to the turn signals, and they are not there on the real car. Be careful when sanding.
3. If Fujimi could call it a DeTomaso Pantera on the box, why couldn't they give us the lettering for the rear panel, or the emblems for the wheels?
4. The painting guide shows the scheme for an early GTS. Break out the Alclad for the bumpers.
This should not be taken as a flame on the kit, because the basic shapes are there. Unfortunately, Fujimi has tried to provide several versons of the car from one basic tool. Get plenty of reference pics, and be prepared for some modelling, and you should be set.
It will be nice to have the kit back, especially if the molds get cleaned up. The Halibrands will be great to have back, too. The only issues I have had (apart from broken windshield frames) is the thickness of some of the chrome parts. The headlight bezels need to be replaced with less prominent pieces, and the grille surround needs some massaging.
IIRC, the fastback roof was based on the unit from the Cougar II show car (Cobra chassis with new body).