I have yet to install my big manis or heat exchanger(been waiting to replace my catch can), so I can't say what improvement they may add. If I had a grand to throw at the car it would most likely be spent on some MT ET Street tires and a set of the lightweight Tolimann wheels that used to be on the CLKs. 13 pounds per wheel. The WaveTrac is $1,295 and I would totally have the 3.27 gears installed along with the appropriate TCU tune...another chunk of change. For what it's worth in the 1/4, practice is the best thing to make the times drop. All of my runs have been on summer street tires and I think I've done pretty d@mn good with that.