new to me 02 S...few questions

[tx02]

I just recently purchased an 02 Boxster 2 and had a few questions.

1 it came with 2 keys. Both keys light up the red light when you press the button, but neither of them actually do anything. One is red and one is yellow, what is the difference?
2 im pretty mechanically inclined and want to change the oil and trans fluid (6 speed) and curious if you guys prefer a certain oil and transaxle oil over certain brands? Where is a good place to get the filter, filter wrench, various sockets etc?
3 when you guys do your own oil changes and trns oil change, does it matter if you use ramps or jack stands? And does the car have to be level or will everything drain out ok with just the rear of the car up in the air?


the only real issues I have with it is until the car is driven about a mile and warmed up, it tries to grind just a bit going into 2nd. Once its warmed up that goes away. Was told some quality transaxle lube might help with that. The next thing is no heat from the heater. Havent had a chance to look, but ive done a search on here and a lot of people have a problem with that flap under the dash. And my last issue is the humming that comes from the gas cap area. Ive read multiple things online of what it could be.

Also, can you guys suggest the best repair manual I can get to tackle these things and anything else that may come up?
Thank you