In hindsight, that was an incomplete statement by me. If you spend $15k to try and boost your home value by $20k, I think you will find out quickly that you are only going to boost the actual sale price by $8-12k.
This was the what I had learned/read as I prepared to sell my last home. And I know of at least one person going through this same experience in today's housing market. Guy's comment on paint and trim to boost curb appeal is spot on. Don't do anything structural/invasive or you will likely lose money.