As you are really getting involved with racing, your plan makes sense, IMHO. Meanwhile until you power up, I recommend my instructor's philosophy. He followed his dad into racing Porsche's about 20 years ago and currently owns about five of the brand, including several 911s. But, his favorite race car is his humble 914, which he did upgrade its 4 to a 6. He enjoys (some would say way too much) beating faster more powerful cars in the corners and expects them to pass him on the straights.When I bought my car, I had no intention of tracking it. I couldn't find a GTS that I could afford and needed a new car right then. My base has the handling goodies of a GTS (PASM, SC, PTV) so I thought the base engine was enough.
It is on the street, more than enough. But on the track, it's already gotten a little frustrating. Having a coach yell, "Gas, gas, gas" and I've already had it floored on the exit - that's when the extra HP becomes very desirable. I had hoped to trade in for a GTS this Spring and make some mods, but now I'll have to wait and see how things go with getting back to work.