Pro 4 Suspension Swap from
http://www.drccentral.com/old/hpi-sprint-rc-drift.html

What this will accomplish-
1) Higher graphite content makes the hubs stronger than stock
2) Allows for conventional turnbuckles to be used for camber adjustments
3) Bearings sit much more snuggly into the hubs, eliminating wheel slop due to the bearing sleeve being too loose or stretched
4) The car will be slightly lower with stock sprint dampeners after this swap
5) The Pro 4 hubs will actually increase the efficiency of the Sprint's belt drive (Spacers that come with the kit allow you to tourqe the wheel nut down without lateraly pinching or straining the inner races of the 5x10mm ball bearings)
6) Your turning radius will be greatly decreased due to the fact that the new steering setup will give maximum sweep compared to stock (refer to the picture at the bottom of the previous page on this thread)
7) Through the use of spacers that secure the hubs firmly and prevent movement along the length of the suspension pins that retain the hubs, you will be able to adjust the length your wheelbase by 5mm

What you will need-
1) Pro 4 Blocks (2 sets) (part #73507)
2) Pro 4 C-Hubs (1 set) (part #73518)
3) HPI Aluminum Washer 3x6x.75mm (1 set) (part #Z814)
4) HPI Aluminum Washer 3x6x2mm (1 set) (part #Z817)
5) HPI Steering Block Bushings (1set) (part # 75122)
6) HPI Sprint Suspension Pin Set (1 set) (part #85021)
7) Dremel tool with cutting wheel
Drill with 1/8 size bit, preferably something that will not mangle plastic but instead leave a clean hole (I used Bosch 1/8 titanium self tapping bit for this)