Over the past few years I've tried about 6 different combinations of v3.5 chip and speaker (standard & micro chips, 23mm round and micro speakers. In the nose, in the cab etc etc) and have never achieved a sound even approaching acceptability. Having heard the superb sound from the sugar cubes in Paul Chetter's 03 at the LYDCC show, I thought I'll have to try these. They sat in the speaker box for six months but today I got round to fitting them, along with a standard v4 chip.
To say they are impressive is a complete understatement. I put two 8 ohm ones in parallel, in the nose, behind the grille which is acoustically transparent. The resulting volume is around twice that of any of any other fit I've tried and more than adequate. In fact the engine sound volume had to be turned down a bit to match the level of the other sounds. Mounting them was a piece of cake, I simply stuck each one using a dod of black-tac on the front of the motor assembly, one above the other. It doesn't seem to matter if they are touching anything around them, in fact they are pushed tightly up against the nose when the body is put back on.
Still a bit of work to go before the v4 sound project is released on an unsuspecting public but I'm really pleased with progress after trying for so long.