[Perfectlap]

Save up for 2009 with the new engine architecture. Everything before it basically uses the same engine design with slightly differing levels of power. The BIG engine power bump didn't come until the very end with the 2015 Boxster Spyder. And then they got rid of the flat6....altogether.
So 986 vs. 987... it really comes down to aesthetics. And always go for the car with the lowest miles you can afford with the caveat that it was owned by enthusiast and not someone who let the car sit weeks or months a time. The longer these engines sit and stew, the worse they fare in the long run. But on the flip side, the higher the mileage (~70K+ ) the bigger those VERY expensive repair bills can be.