I've heard the car analogy before, and one reason why I think it's a bad one is that a car is something that you use. People shouldn't be something that you use. And if you love someone enough to want to marry them, I think you can work out sexual issues.
Yes, of course it's not a great analogy. The point being that if people are willing to put that much research and effort into choosing the right car, it would stand to reason they would do at the very least the same when choosing a life partner. There are certain aspects about buying a car that most people simply wouldn't skip because they hold more importance. To use another bad example, someone might not check every tire specifically to make sure it has the perfect amount of air, just like most people wouldn't not marry someone because their earlobes are slightly different, but most people wouldn't commit to buying a car without first seeing if it drives nice.
Also, it sure is wonderful to know that your partner isn't comparing you to someone else, and that you aren't comparing your partner to someone else. I think like a lot of good things, waiting for marriage to have sex is difficult to achieve but well worth it. I think it's a gift that is saved up for the person that you want to marry.
No offense, but I don't feel this is a great argument.
You're assuming that all comparisons will be negative when in fact the comparison could easily help to solidify the marriage as that person would know that they are more compatible than past partners. It's using the argument that ignorance can only result in good is like saying you have never eaten live larva before, so when you finally do, it will be great because you have no other insects to compare it too.
As well, you could also argue that because two people have nothing to compare sex to, it has the potential to spark the "grass is greener" mentality. When you've had enough sexual partners to form an opinion on what you do, and don't like you are able to eliminate certain things that you might otherwise wonder about. For example, I prefer girls with smaller breasts, and while that wouldn't be a make or break if I met someone amazing, I will put more effort into what I do like, than what I don't. I think my wife would rather me be solid in that conviction than spend my life sneaking peeks, wondering what big breasts feel like, and if I like them better.
The truth is (and this comes from experience), despite best intentions not all people are sexually compatible. Sometimes they're not physically compatible and no end of trying will ever change that. That's not to say you need to have sex with 200 people before you get married, but I feel that in order to make an informed decision you need to have enough experience to know what will, and won't work for you. It's not always the case that two people can simply work out sexual issues, in fact this is my point, you can eliminate many of those issues by exploring what you like, and how your potential life partner interacts with you.
Imagine if your wife/husband suddenly decided they were into S&M and you only liked your tried and tested missionary position. There is going to be a point there where in order to make it work, both of you are going to have to have sex they don't like. It would seem much better to me anyway, to know you don't like S&M, and to know that the person you're marrying does before hand.
And as far as those silly arguments about wanting to be experienced on your wedding night - how ... I don't know, I guess vulgar would be one way to put it. As if you loved the person because of how they could perform. As someone who was a virgin on her wedding day, and who married a virgin, I can tell you that we had no problem at ALL having fun on our wedding night! It was really special to know that we both waited and could explore this wonderful area for the first time together.
This has nothing to do with the wedding night. I have had days of horrible sex with people I have been with for years. What matters is how sexually compatible two people are for the duration of the marriage. The wedding night isn't like a one time Olympic event that you need to train for, and in the big scheme of things matters very little. Anyone can get a "high" and fudge together a wedding night of sex, its the same reason why strangers can pick each other up at the bar and have one night stands with fairly good success.