Bro you need to consider these facts.
Bank interest will be high for Altezza cos nearing the 10 year mark. Are u ok with it ?
Buy and repairs for 10k is too much...... 2k should be enough for major service wear & tear parts change. Unless you are saying you are buying a car where engine and gearbox caput then yes.
The chances are slim for this to happen. Last I checked 6MT Halfcut cost around RM 7.5K FYI.
Altezza comes with 3S-GE and 1G-FE. Converted to D4 I cannot comment much cos dont know
the halfcut condition and how the installation done. Beside altezza doesnt come with D4 and the halfcut is from another model. So if not installed properly sure got issue later.
If standard 3S-GE then shouldn't have any major issue..... one tough engine except for throttle
body after 10 year may give problem. This can be changed with new or used unit.
The auto gearbox is already 10 years old so may need some repair if the previous owner never
change the oil. If need to replace then standby RM1.5K to RM2.5K. The only thing that can be
a bit costly is the suspension parts cos double wishbone all around. Again there is still an option
for used unit from japan if u prefer.
Again are u sure u are willing to spend the time and money?

If you are it is a rewarding car to own & drive.....

Pls consider wisely. Only for enthusiast.......
BTW correction "lower maintenance cost to vios" reference to auto gearbox. what was meant was similar cost. The 5 speed auto does not require special gear box oil. The 4ltr Toyota Type IV RM80
is enough.