You will definitely want the better wheels .... so why not buy the better bike which already comes with them? When you amortize the cost out over how many miles over how many years, the difference disappears. The joy of the ride remains.
There is no such thing as "too much bike." Most people don't train as athletes to their maximum level, so they are likely never getting 199 percent of what their bikes could do anyway .... and given open vs. closed roads, and random pavement conditions vs. having a team check the route many times in advance ... riding all-out for more than very brief stretches would likely have severe negative consequences.
If we applied the same thinking to our cars, we would all drive Ford Fiestas or something.
The question is, which bike is going to provide the most enjoyment of every moment during every ride----and the marginally smoother ride and much better wheels of the CF TCR will do that. Life is not about calculating costs ... it is about experience. The better bike will give you better experiences. it will improve your life.
The Al TCR is a great ride .... and wheels equivalent to the SLRs will make it much better ... for the same money. But still, probably not quite as good as the CF version. Buy the better bike for the same money.