Yes, its possible
A better advice would be to change the stock speakers too, because the sound quality of a Basstube would not mix well with a company fitted stock speakers.
If you are on a tight budget i would suggest you to break the setup installation into 2 parts,
1)First change the stock speakers with Components in the FRONT and Oval speakers to the REAR
This will give you a smooth and crisp music experience.
2) Add the Bass-Tube with Amp for the extra Thump later as per your convenience.
First of all thank you for your advice.
1.I'd like you to know that the stock speakers in my Xcent are pretty good, not the best but gets the job done. The only thing it lacks is the BASS. That's why I was opting only for the basstube with built-in amp. I'm only confused in- "would this upgradation will get my job done. And also the technicalities like RMS and all (I dont know this stuff) would be all fine or not? If the above option is good then I'll be happy to go for it(considering my low budget) and if not then I'll go for the option below. I just want to know which is best for me.
2. I would like to know that installing 4 components instead of 2 components and 2 oval speakers would improve sound quality or it will be the same?
Also which option is better: - 1.Basstube with built in amp.
2. Basstube with external amp.
PS: - This all upgradation is going with Stock stereo.
Thank you.