||I got this because I was having problems with my Tokyo Marui 5.1 Hi-Capa and was hoping that something in this kit would fix the problem. I will go over my experience with each part in detail:
Loading nozzle - 3/5
The nozzle seems standard and in no way special, simply a replacement part. When putting this part in my Tokyo Marui, the performance decreased, so I'll be sticking with the stock TM nozzle.
Piston head - 4/5
The piston head looks very nicely made. It has eight ports, made of aluminum, and has a nicely made o-ring. It provides a tight seal with my stock TM nozzle and an even tighter air seal with the nozzle that comes with the kit; normally, this is good, but it may be a bit too tight, so the nozzle may be able to get stuck, but I haven't encountered a problem so far. I am using this piston head over the stock TM piston head.
Cylinder bulb - 3/5
The bulb is good as well. It has an o-ring to help guide the gas so it doesn't escape, but I doubt that it helps that much. When installed, I noticed a bit of an FPS increase, but nothing to freak out about. I am using this bulb over the stock TM bulb, mostly because the stock bulb is plastic.
Recoil spring - 5/5
I am very happy with the recoil spring. It is stronger than a stock TM, a stock WE, and a Guarder 150% recoil spring, just as expected. I am using this in my TM and am very happy with it.
Hammer spring - 2/5
I was VERY VERY VERY disappointed with this spring. It is VERY nicely made, but was disappointed with its strength. It's stronger than a stock TM spring, but it is weaker than a stock WE and Guarder 150% hammer spring. Very disappointed with that. I won't be using this hammer spring in, well, anything. Ever.
Overall, this is a good kit.
Rating: [4 of 5 Stars!]