My daily driver is a 91 LH3.1 stick shift wagon. LH2.4 cars are a little quicker. Most of the mods are in the suspension. 25/25 bars, Bilsteins, firewall braces, strut tower brace, sport springs, wider wheels and tires. The car runs a B cam with a Dales adjustable timing gear 4 degrees advanced. Being a stick shift car it is already quicker than an automatic, even though the 3.1 is tuned more for economy. Car has a 2.5" exhaust front to back including the cat. While it is no barn burner, it is quicker than a stock 245. The bonus is in the handling. This car can be drifted through an on-ramp it is so stable. It does have polyurethane torque rod bushings and will soon receive poly trailing arm bushings too. If the car is an automatic, there is little you can do "simply" that will improve acceleration noticeably. The heavier cams noted, VX and up, will make a difference though.

Generally speaking, just putting in larger injectors makes little difference if the injection system has no reason to flow more fuel. However new injectors always perform closer to spec, so that may improve performance by itself. If your injectors are 20 years old and have never been cleaned professionally, then you are surely loosing performance and a new set will fix that. Spray patterns have been changed on the newest injectors too, to improve performance.

Turbo upgrades are great, as long as you can get them past any equipment inspections at smog time. Don't know if that applies. Here in California, getting a turbo into a late model 240 legally is a hassle. I'm about to do a twin cam conversion for my car, no turbo. With the other mods I've planned I'm hoping to pick up about 40 horse.