This thread is finally getting to the point. To summarize:
1. The picture is much larger than hp and tq.
2. From a mechanical standpoint, it's a holistic thing - it's about the whole car. A simple dragging caliper can invisibly negate all that expensive hp. A poor setup can delay you from getting back to throttle out of a critical corner by a precious tenth or two, again negating the benefit of a monster motor. Neglected maintenance can result in broken belts and leaking hoses, resulting in DNF's or worse. The list is almost endless.
3. Fundamentally, building a car, maintaining it and prepping it is not about money: it's about time and knowledge. If you have the time and the know-how (oh, and a body shop, mechanical shop, machine shop and a few hundred pounds of tools), you can build a front running national-level SM for less than half the cost of a the best pro-built car. If you have to farm out the motor and trans, the savings are less, but still substantial.
4. For those of us who lack the time and/or knowledge, money is the only alternative. Fortunately there are people who know what they are doing who are willing to spend the time necessary to build an engine, a trans, a cage, or an entire car in exchange for money. This allows a great many more people to successfully compete in SM than if everybody had to do their own work. Hooray for free enterprise. Unfortunately, for those who have neither time, nor knowledge, nor money, driving a top-level SM is pretty well out of reach unless you have a really, really good friend. But take heart - for most drivers, it wouldn't make much difference anyway. See (5), below.
5. In the end, it comes down to the driver. At some point, time and money spent on car build and prep runs up against the law of diminishing returns. Beyond that point, the driver is better off working on himself rather than the car. For the vast majority of drivers, that point is well short of $40,000.
6. Which brings us to the final point - money can buy a great car, and it can buy a crew and even a coach, but, in the end, acquiring the skills it takes to run at the front in SM takes a huge investment of time and effort by the driver. It also requires the driver to look at himself first when searching for speed. Blaming the car is a fatal trap. When I first began racing, I didn't own a car. Instead, I drove Tom Fowler's rentals. I knew Tom's cars were quick because, on test days, he would put down laps so I could use the data for comparison. It was humbling. For two full seasons, each time I came in from a test, qualifier or race, the crew would ask me, "How was the car?" My standard answer was, "Still faster than I am. Don't change a thing." Only when I felt I had fully mastered the basics of car control did I begin experimenting with setup. Once I was convinced I had fully exploited the potential of the rental cars, I had Tom build a car for me. It's a top build and I won a regional championship in it...but I haven't come close to a podium in a Majors. We'll keep working on the car, but it's already good enough that I doubt there's much more speed to be found there.
It's down to the driver.