Welcome to the forum Angel -
For only being 21 you have owned a lot of cars (kind of jealous actually). Obviously from my sig you will know I have some bias towards 04 S.
Before I tell you my preferences... look at NickCats thread on buying used Boxsters, it will really save you some headaches and money. Get a PPI, best investment I made before I bought my car last year.
04S vs. 05 base... a difficult decision indeed. I think it really comes down to your tastes and preferences. I think you know that Porsche tends to make slow evolutions to their cars instead of drastic revolution. In 05 they made some real changes to the Boxsters instead of modest little design changes. Renzop makes some good points. It is always good to buy the newest you can afford - especially when it comes to Boxsters. With that said:
1) Styling? - I am not sure that the 987 is better. Many 986 owners like the what we call "edgy" styling of the headlights, while other like the more oval smooth styling of the 987. It is more in line with the 993's. This is more of your preference. Non-Porsche nuts will not be able to tell the difference between MY98 in great condition and a new Boxster.
2) Interior is much better in the 987 than the 986. It is roomier (I am not sure if you care) with lowered seats, wider seats and much more head room. It is safer, it has 6 airbags including head airbags and higher roll bars.
3) More standard features in the 987... true. However, you have to make sure you are not comparing a stripped down version of an 05 vs. a fully optioned 04S. My 04 SE was fully optioned and had everything I wanted. Porsches have lots and lots of options and customization..... get the car that you want.
4) Bit less hp and torque in the 987. I am not sure that I will be able to tell the difference. But for your info the 2004 S - 3.2L 258hp 229lb-ft; 2005 - 2.7L 240hp 199lb-ft. 18 Hp?.... I am not sure I could tell the difference. 30lb-ft of torque?... I think that I could tell the difference in grunt. I think 2004 S will feel faster to me because of the torque, I am not sure that it would be faster than a standard 05.
They also freed up the exhaust to make it less restrictive (better sound? cannot remember)
5) As I posted elswhere on this forum the 04S brakes rotors are the same size and set up as the 05 base. I am not sure about the suspension set up though.
6) Shifts are more precise and "tighter" in feel in the 05. According to Porsche, they supposedly reduced the throws by 27 percent in 05 compared to the 04. In my SE, it comes with a short shifter and I really like the feel of it. However, I could tell some difference between the 05 and 04 shifter when I tested them. (I, at the time chaulked it up to abuse and mileage of the vehicles)
7) 04S is a 6 speed, 05 is a 5 speed. There are obviously differing opinions on what is better. Many owners of the 5 speed as well as magazine (Excellence) articles talk about how the 5 speed tranny is much better suited for city driving as well as spirited drives in the country side. I really like my 6 speed but I have not spent enough time a 987 5 speed to know the difference.
With all this in mind, what would I choose? Hard to say, difficult decision. I would encourage you to buy the newest one you can afford but I would miss the torque and options on my car.
You should also wait patiently for members who have actually made this switch, rather than an insomniac like myself who is trying to recollect what it felt like when I went Boxster shopping last April. I know there are members who made similar changes from an 986 S to an 987 base.
Good luck, no matter what... you will have a good summer.
