Done with both sides. I it was a cold as it gets up here in NJ. I had propane heaters, 2 pairs of socks and gloves on and those little bag's of chemical heat in every pocket but still couldn't get it done in one go. Whatever it takes though. This one's running good now possible 400 hp with intakes modded and exaust opened up. And she'll hit 8300rpm so 60mph is no longer a 3 gear affair. 0-60 varies on temp and humidity but I have never lost to anything else off the line thanks to the tranbrake