porb. the best tips I have would be:
1. Make sure your car runs great before you spend money on making it look great. a brand new looking 944 will not do you any good if you have to tow it behind the wife's miata cause the engin dont run.
2. If you plan on spending (50% of the purchase) or more on a car for added extras. then you have to realize that would have to drive it twice as long just to get your money back, cause selling it wont.
3. Spend the extra money on good lubricats.. Mobil 1 (it does pay of)
4. Service your car or get it serviced regularly.. (Remeber your timing belt, water pump and pullys. premtive maintenance is king)
5. IF IT AINT BROKEN - DONT FIX IT (but see point 4 above)
6. Get as many quotes as you can before you send your car in.
7. When you get it back. ask for the replaced Parts.(you will be supprized how the ** you)
8. Tech. forums is your friend. Ask questions, play dumb. (I would rather look dumb. on a tech forum like this. Then look $2000 dummer infront of the Girl Friend)
9. Baby needs new Shoes. (check - recheck-upgrade brakes and tires, afterall it's what keeps us mear mortles on the ground)
10. Test your wiper blades. You dont want to be stuck 60 miles from home cause you forgot to test your blades last summer.
11. When you working on any electric's remove the ground (brown) wire from the battery. (ps. remember to reset your clock)
12. Check for oil leaks under your car as you approche it whenever you can. (you dont have to bend down and look uneder it, but it saved me $4000 on a blown engin. The oil sump drain plug fell out.)
13. Look at your guages in the car. I know they are not all that acurate but it will show you if you had a burst warter pipe and the car is heating up.
14. Listern to your car once a week.(i have a really big audio system in my 944 and I would not even hear it if my wheel fell off. so once a week i drive to work with the radio off), You know the sound of your car better than anyone out there. You would be supprized to see that you would be able to hear a fault long before it happnes.
15. Dont drive your car like you just stole it. Cops might think the same thing. and you know what would happen if you live in LA
well enough for now.. that was prob. my 4 cents.. till later