Right, here you go mate!
Start off by removing the two little screws either side of the engine...



and you should be left with this, after you remove it from the chassis...



simply remove the springs and the 'axle' from the posts, and add 3 little washers to each end, like so:



Then simply put the axle back on, followed by the springs, tighthen the screws, and you're done! and they're very discreet once fitted(i have only done one side in this picture)



Now for the back, same goes here as it did for the front... remove the two springs holding it in place :



so you're left with this...



now same as the front, add the washers, i only added two on each side, but it's upto you as to how many you fit.



simply do that, re-fit it to the chassis, and there you have it!
hope this helped mate, let me know if you get stuck on anything!