Please please please dont go for the 2001, add some money, but look for the face lifted one.
Other then that if the car is a-okay, no major accidents, no awkward noises, go for it eyes closed.
Parts, Every thing is avalible, Taiwanese brand new, each and every spare park, 80% of the car is a Vitz, rest 20% parts, lights bumpers etc can be found in the market very easily.
Spare parts prices arent too high, infact very much competitive with suzuki/toyota/Honda parts.
As if u keep the fact in mind that even local cars spares are often taiwan imported.
A brand new Vitz bumper costs around 4k, a pair of head lights is Rs.6000 (taiwan brand new).
-air filter, rs. 250
-oil filter rs. 180-250, Toyota Genuine (compatible to local and imported toyotas) Rs.600
-Brake pads (same as Xli-Se-saloon). (costed me Rs.2500 or 2800 il recheck)
-Even the spark plugs are same as of a Corolla 1.3L, k-16r-u11, avalible for rs. 150 a peice.