I also run the J cvd's all the way round also as the price is better if you break them and less play in the tire and axle when bolted together. I believe the J is lower in price due too no carbon fiber. I love this car alot, but parts prices are a little high. I have TC5R I race also and I have the TiR world's Cvd's and they are not as much as the stock ones for my E4rs. I have yet to break or bend one either. I have been emailing them aobut a possible part for the E4 and I think it may happen but not holding my breath. I would certainly buy them.