A front one-way is a diff that goes in the front gearbox which allows the drive shaft to provide power when you are accelerating, but when you are coasting or braking it "free-wheels". It is faster, provides more speed through the corners, but makes braking difficult as you only have brakes on the rear wheels. Not a beginners thing, and not necessary on a TT01.
Aluminium parts are a waste of money, plain and simple. You don't see ali gear on pro cars for a reason. My racing cars have ali motor mounts, and 1 has a bulkhead brace, that's it. If you want strength get Carbon Fibre, but again, not really necessary. You could get an ali prop-shaft if you don't already have one as it will handle more power from the motor.
Upgrades, in order, for entry level racing should be:
1. Full metal bearing kit. Doesn't need to be Tamiya, most knock-off's are fine for beginning. Although I think your car has them already.
2. A set of tuning springs for the shocks. Tamiya has them.
3. Upgraded ESC. Get a known brand, that can handle to about a 19 turn.
4. Upgraded motor. Again, known brand.
5. Pinions to go with the motor. THis is the biggest mistake most beginners make. I think the TT01 has a few fixed options for pinion selection. Get them and try them as all motors have a different "power band", which you can find by trial and error by gearing the motor differently.
6. New battery. Soon that old 1300 NiCad just won't cut it. Bigger capacity batteries are heavier, but give more power.
Anything else when you are starting is just for show. It won't make you faster, so why get it
A little more on the motor thing. The Tamiya RZ motor is fine for beginning racing, expecially on a small track. I have a TA-05 for my on-road car and with the right gearing, the RZ is a rocket. It also lasts a long time before needed to be re-built. I have had dozens of different motors, and for ease of use the Tamiya is well placed.
The main thing with a TT01 is it's a fun car. It is competitive against other TT01's and similar entry-level cars, and that's where you should aim. They are very popular cars for a reason: Easy to set-up and easy to drive.
Sorry for the lecture.....