You need taller rear tires. What do you have now? With stock dia tires you should be able to cruise comfortably at 100 km/h with the lowest stock R&P.
For a daily driver that sees frequent freeway use, I recommend a 4.12 R&P (you probably have a 4.37 R&P) with stock gears. If you are gonna go to the track, you need a 9 tooth first gear and a superdiff. If you want a 4.12 R&P, the best source is to get a double side cover IRS trans, then use that as a basis for a strengthened swing axle.