I just spent 4k for 100k maintenance parts, fuel upgrades, tune, and some supporting parts. In addition i still have to buy a turbo! One nice thing i was able to get everything i needed from Infamous so it was a one stop shop with great deals but things definitely add up. I could have gotten by a lot cheaper but I didn't want to half ass it. Spend some time reading this write up, very nicely done.
http://legacygt.com/forums/showthread.php/turboi-wiki-twist-178684.html