1993 Camaro Z28 (Less than 100,000 miles)

1993 Chevrolet Camaro Additional Info:

I'm selling my 1993 Z28 with less than 100,000 miles. I'm the second owner, and I've owned the car since November 1998. First, the good. The following is the list of modifications (and part numbers, when available), along with the installation dates I could remember:
1993 CHEVROLET CAMARO Z28 (A4)
#840 OF 39,739 TOTAL CAMAROS BUILT
96,800 MILES: ALL OPTIONS EXCEPT T-TOPS
K&N Filtercharger Injection Performance Kit
Trick Flow aluminum intake elbow (Summit Racing part number TFS-3150801)
Trick Flow 58 mm throttle body (Summit Racing part number TFS-24258)
Trick Flow 54 cc aluminum cylinder heads (intake and exhaust diameter: 2.02" and 1.6"; intake and exhaust runner volume: 185 cc and 67 cc) (Summit Racing part number TFS-30400008-M54)
Hydraulic roller camshaft (lift 234/242 [.539/.558]) (Summit Racing part number NAL-19244485)
Trick Flow 7.2" chromoly pushrods
COMP Cams 1.6 roller rockers (Summit Racing part number CCA-1602-16)
ACCEL 300+ digital ignition and ignition coil
NGK TR55 IX spark plugs and Taylor Spiro-Pro 8 mm plug wires
March underdrive crankshaft and alternator pulleys
Hotchkis shocktower brace
PaceSetter ceramic-coated long-tube headers, dual catalytic converters (hollow), X-pipe, and Bullet race mufflers (3" true dual exhaust system with 3-1/2" outlets)
Superior 700R-4 HP shift kit (part number TMX342-2804)
B&M transmission cooler
TCI StreetFighter 3,000 RPM torque converter (Summit Racing part number TCI Auto 243105)
Yukon 3.73 gears (Summit Racing part number YGA-24146)
UMI Performance single-adjustable rear control arms and single-adjustable panhard bar (Summit Racing part number UPI-201621-B)
Tuned computer chip
SLP manual fan switch (Summit Racing part number SLE-63011)
2000 Pontiac Trans Am WS6 wheels
JVC El-Kameleon AM/FM stereo with CD player
Sony X-Plod 6-3/4" rear speakers
Red under-dash neon lighting and interior lights
Reverse-glow gauges (red)
DYNO RESULTS
Horsepower--375 rwhp (450 hp at the crankshaft)
Torque--327 ft.-lbs.
INSTALLATION DATES
Headers installed August 2010.
Top end of motor rebuilt and computer retuned summer 2013 at 90,500 miles.
Exhaust installed September 2013.
Yukon gears installed January 2014.
Rear suspension components installed March 2014.
Torque converter installed November 2014.
Optispark replaced October 2016.
Superior shift kit installed and transmission cleaned and inspected May 2017.
Now, the bad. The major problem is that I just lost third and fourth gears, so the car won't go faster than 45 mph. I don't know if the problem is the throttle valve and 3-4 clutch pack, or if the problem lies deeper in the transmission. When the new shift kit was installed, I was informed by a transmission expert that the transmission was fine, even though I knew something was wrong with it. Other than that major issue, the A/C doesn't blow cold, and the passenger side window is slow to rise, which is normal for the fourth-generation Camaros. The paint needs some TLC, but a wet sand could probably bring most of it back, and the hood stripes are mostly deteriorated. The hatch struts need to be replaced, and the fuel gauge on the dash cluster doesn't work.
I'm asking $3,500 for the car because I don't have the time or money to put into it any more because of life responsibilities.