whats a cheap way to make my VW 1.8t jetta have better performance and quicker?

Very simple answer: new ECU programming. Use search engines to look into GIAC, APR, REVO, Upsolute, and Autotech. I would recommend either of the first 3 I mentioned. This will add a SIGNIFICANT amount of horsepower and torque to your car. I would recommend replacing the factory diverter valve (DV) with a Forge or Bailey Motorsport onefor reliability, as well as the factory air filter with something higher flowing, such as a K&N or ITG. If you crave more after that, replace the factory exhaust. That's all you need.

First off, it isn't a V4, it is an I4 (as in, inline 4).

Assuming you have a typical American market VW, go to a wrecking yard and buy a 5 speed manual transmission, clutch, pressure plate, and flywheel. Pick up the clutch pedal assembly and the cable or hydraulic system for the clutch too. Execute a transmission swap to manual. Install a new, quality, clutch kit. While you have the tranny off, change the rear main seal (crank) and the tranny seal too.

From there, look into a cold air intake and oversized (more free-flowing) exhaust. If you can afford it, try swapping the turbo out for one off an Audi TT. The cats on VW's can usually take some tuning and more HP than the stock engine. Install some iridium plugs and performance wires.

Add some upgraded brake rotors, brake pads, brake lines, and brake fluid (not DOT 5 - you'll have to clean and/or replace extensive parts of the brake system). You don't want to go faster and can't stop better. Don't forget to bleed the brakes by the book!

That is to start with. From there, as your budget allows, you can look into slightly more aggressive cams, injectors, and P-chips. For a daily driver, you don't want to go too aggressive. But, for a purely track car, take it where your financial advisor allows you to, then push him.