Our downloads have alot of logos and numbers, but so does google and other sim sites around.
The biggest thing you need is patience and faith. Show off your work and accept constructive criticism for what it is... constructive. Every paint scheme will get better. And don't fret if it takes 6, 8 or 24 hours to paint a car. It's a process.
Also, there's TONS of tutorials on the internet for PSP and painting cars. Use google. Ask questions. Be specific when you ask though... tell folks exactly the problem you're having and others will usually help.