My buddy just bought his so he has not done anything, and if I owned one, I would have to get a larger toilet first before I could "modify" it 
Two years ago when we bought our 1:18th Nylints, the 1:6th Nylints were $149. I've never see it for anything less... But I rarely go to Walmart
well...its kinda cool to me because its getting my girlfriend into "wheeling", actually she took my truck and went to get more rocks with her nephew to build a longer track...but anyways , if you can get a bigger toilet, let me know cause i got some big crap to flush down it
