There should be a sticker under the hood that will show if it did or did not have a cat. Though they likely will not look for it or the cat, that ARE supposed to. You are not, under penalty of federal law, allowed to remove it regardless of what anyone tells you. I have also heard very little improvement in removing them supposedly.
As far as the window tint I know that the law states no darker than 35% on front two windows, but it is not listed as an inspection item on the following list from Texas DPS.
Here's what's inspected by vehicle type.
Items of Inspection
--------------------------------------------------------------------------------
05.02 Inspect Every Pickup, Panel, or Truck Under 80 Inches Wide For: (Listed in suggested order of inspection)
* Check for evidence of Financial Responsibility
1. Horn
2. Windshield Wipers
3. Mirror
4. Steering
5. Seat Belts
6. Brakes (system) Parking - (beginning with 1960 models)
7. Tires
8. Wheel Assembly
9. Safety Guards or Flaps (if four tires or more on rearmost axle)
10. Exhaust System
11. Exhaust Emission System (beginning with 1968 models)
12. Beam Indicator (beginning with 1948 models)
13. Tail Lamps (2); (1) if 1959 model or earlier
14. Stop Lamps (2); (1) if 1959 model or earlier
15. License Plate Lamp (1)
16. Rear Red Reflectors (2)
17. Turn Signal Lamps (beginning with 1960 models) (mea-sure if 1959 model or earlier)
18. Head Lamps (2)
19. Motor, Serial, or Vehicle Identification Number
20. 1988 & newer - inspect for window tinting or coating
21. Gas caps on vehicles 2-24 model years old.
Overall width is determined by measuring from the widest part on one side to the widest part on the other side of the vehicle. In some vehicles this may be the dual wheels which would be considered as part of the width. Do not include an outside mirror or mirrors in determining overall width.
