Hi:
The issue with the track width is that you cannot use too many spacers without losing the pins that hold the axles together. The reason why we came out with our axles was for that reason and because the 3 piece axles wobble. They wobble even more when you use spacers to the point that the pin is ejected on the straights. We have received word from team drivers that just the axle change is worth .5 seconds per lap. We made them in increments from -.25 mm to +.75 mm. I usually run +.25 mm on my car to get close to the 190 mm limit.
We continue to recommend the E4FS as the car to get for stock motor use. It is too bad that they called it the foam spec car because it has proven itself to be awesome on asphalt. As proof it is the only car we will send to team drivers. For novice and intermediate drivers it can take a greater impact and not get tweaked and for all drivers the stiffer bottom deck has a major advantage in that belt skipping is reduced. The greatest area of parasitic drag on the entire E4 line is that if you try to combat belt skipping by tightening the belts it WILL slow the car down. For a long time drivers thought that the E4 was inherently slow because of the 3rd belt. We have proven that the real culprit is that the belts are usually set too tight. We have posted our recommended method to set belt tension on the car. You can email us if you cannot find it. For Christmas we reduced the E4FS to its lowest price ever. We put a certain number of cars aside for this sale and when they are sold out it will end. We have received a lot of orders so far and it looks like they will run out before the 25th. Contact us if you think you're getting cash for holidays. We'll let you know how to have one set aside.
The list of add-ons can improve the car but we recommend that people start off with the LiPo kit WH10135. The aluminum caster blocks are a good upgrade but whether you really need them or not depends more on the track where you run. We have some customers that go through them pretty fast and we have others that have never broken one. Needless to say those that break them consider them weak whereas others wonder what the big deal is about. One item that we are really happy with is the WH10131, the lightened and hard-coated layshaft. It solves a lot of bearing issues and we haven't seen a single one wear out.
We have extended our Black Friday sale on parts through Christmas to help you all out. Just use discount code: parts15 to get 15% off.
Happy Holidays and Merry Christmas