You think like me. But most people are afraid they can't master it and prefer to start at a lower cost. I like your stand. Invest bigger then the commitment to practise will come.
A difference of RM500 is not going to separate the entry level and mid range level. Tell us your budget and your music background. If you want to start off with a mid range guzheng, it should last you till your are done with the exams grades. Going for top range then become a question of your fussiness. Choosing a guzheng is not something you can learn by reading because music requires the sense of hearing. This ear for music is cultivated through experience.

G8 piano means last level right?
I think you can move very fast with guzheng. Practise for the first few months are all about timing. Since you done piano, you know how long to hold a whole notes, half note, etc ... Once you know notes on the guzheng like how you know the piano. Tell your teacher you can want to express through the basic. I had a classmate who plays the piano well, going express speed from beginner to intermediate level in one month.
You budget will still get you an entry level instrument. RM2000 guzheng will not sound any different than one that cost RM3000. This level is like buying lottery situation I explained earlier. You be lucky if you can get a mid range instrument for 4k. 5k would be a more reasonable budget to get a mid range guzheng. If you can't buy the mid range I advise go for secondhand.
KL is a bad place to find guzheng. I almost bought the set you mentioned because that seem like the only place in KL that sold guzheng. What prevented me was the backboard is black in color. Painting a backboard (and black of all color) indicated the manufacturer wants to hide the type of wood used for the backboard. I am not saying chamber music is bad. They had carried good products on their shelves. I can only say they dont know guzheng which is not a popular instrument here that well.
Subangman is our shopping expert here. He know all the shops sell guzheng in Klang Valley. He also the location of all the school. If he is not busy he will tell you. Otherwise look through back pages as he had listed them several times. Keep us posted before you make a purchase and we will try our best to guide you. There are so many thing involve in buying a guzheng and it is not easy to cover them all.

Music is a universal language. It does not matter what language you speak. Only you may have problems understanding the teacher if he only can speak Chinese.