There are a group of 6 of us here locally in the UK that are running the E4 in various guises, and we are on the whole very pleased with our cars.
Last weekend I ran a whole lap faster than my PB on that circuit and would have got two laps had I not bust a wishbone on the last lap of the last final, the car just kept getting faster all day, and the conditions were far from ideal with temps only just getting above 4 deg C all day, I had grip a plenty, and I was chasing a gear ratio for my new brushless as well so there was still more speed from that to come!! A fellow competitor took the track record by a large margin and one of the other competitors improved by a good margin as well.
So for all the doubters out there, the car is fast not just in the more experienced hands but also in the hands of the lesser mortals (me), I would recommend it to anyone and a couple of people have bought them on my recommendation and have been very pleased with what they have got, it is a little different to the norm, and it may be a little bit different to what you guys are used to, but it is a superbly engineered car that proves itself time and again.
For me 9/10 very highly recommended, but that is only my opinion!!! (the only way a car is going to get a 10/10 is if it drives itself to the track record and WC every time I put it down!!!)