This is a great value chassis and is easily customized and without much budget. Overall, a great car, with many mods available, but you only need a few if you are on a budget? A brushed/NiMH setup is also cheaper than going brushless/LIPO, if you are sticking to a budget? I run mine with a brushed motor with 5000mAh NiMH (not Brushless LIPO).
The Sakura D3 comes with a STD 2.14 CS Ratio (meaning the rear wheels spin 2.14 times, to the front spinning 1 time). If you find it too hard to drive right out of the box (which is common for many new CS drivers), you can reduce the Front Gear from the STD 38T/13T to a 35T/13T (Ratio changes from STD 2.92 to a reduced 2.69). Then also reduce the Centre Pulley Gear from the STD 22T/13T to a 19T/13T (Ratio changes from 1.36 to 1.58 and a final CS drive ratio 1.70) or a 17T/13T (Ratio changes from 1.36 to 1.76 and a final CS drive ratio 1.52). These setup changes are relatively easy to do. * If you do this, make sure to re-tension the belts by adjusting the "Bearing Holder" from the STD 3rd hole position to possibly the 2nd last or last hole position (Refer to Pg5 of the D3 CS manual).
Upgrades: 1) I recommend getting the Front One Way SAK-D324/PK (replacing the STD 38T with the 35T gear on if you want to reduce the CS Ratio?). 2) The Ultra Wide Universal Joints (SAK-D331) which should be fitted with, 3) the Aluminium Steering System (SAK-D310/PK). 4) To reduce the centre belt slack, buy the Centre Belt Tensioner for the Sakura Zero (SAK-58/PK or SAK-58/BK). This fits the D3 perfectly (there is no D3 part). 5) A spare set of belts is also a good idea. Have fun and happy drifting!