Not sure I would've paid 10k for a 10 year old car that's in "almost good" condition anyway. Aren't most 02/03 wrx's going 8-9 these days? And that's in virtually mint condition.
Your buddy didnt even check the title first? Sounds like the "scammer" is very good at not answering questions he's not asked.
If the car is fine other than those few little things, fix it, run it, and enjoy it. Trying to resell with this information now would lose you more money. Not to mention make you a worse person than the seller if you didn't disclose it.