The usage of 'as in' in a sentence starting with 'nor'

The Elantra Sport is a fun car to drive, even if there isn’t nearly as much front-end grip as the newest Civic Si, nor does aggressive trail-braking net any oversteer in tight turns as in the Ford Focus ST.

I suspect your difficulty with the long even if clause may have something to do with how this conjunction is used and perhaps with another meaning of as in with which you might be confusing this particular usage.

Even if…

Even if introduces a concessive clause despite which a statement is still true. It may be used for unreal conditions:

As I drank to quench my unquenchable thirst, I thought to myself, “Even if I drank the ocean, I would still be thirsty!”

With real conditions, even if is equivalent to even though or although:

Even if you're between jobs, stay active and open-minded; even if you've landed your dream job, maintain outside interests.

You do not have to buy your child sugar-coated cereals if you don't want to, even if he has seen them on his favorite television program and puts pressure on you to buy them.

In your sentence, the Electra Sport is still a fun car to drive, even if one concedes that the Si and Focus ST both have attractive features the Sport either has less of or lacks entirely. And yes, the author implies that front-end grip and oversteer in tight turns are desirable features.

As in…

As in as a single unit means ‘in the sense of’. It’s often used to talk about the meaning or pronunciation of words:

In your sentence, however, as and in keep their separate meanings: the preposition in is incidental:

In Germany as in most countries, there is a big lack of skilled developers.

In Germany— as with most countries— the Japanese kaiju/science fiction boom kicked off with the release of Toho's GODZILLA, which opened in theaters there in August 1956...

In your sentence, as the newest Civic Si and as in the Ford Focus ST are in parallel, giving specific examples of the features described more generally. The preposition in could have just as easily appeared with the Civic. In fact, the meaning would have been clearer had the writer done so.