Me Too!!!
I think your next investment should be an EBC. Its strange that the previous owners have spent $20k+ on support mods and yet no EBC has been installed.
Also, +1 for ditching the MAF's, go for a vipec/link or haltech MAP setup. Remember, a good safe tune will is the best thing you can do for relibility.
IMO if you plan to keep the car off the track, installing the above two items should get you ~500+rwhp, which is ample for the street. If the plan is to track the car, an upgrade the oil system is a must with an extended sump, baffels and new pump. This has been covered in mant topics so i won't go into further detail