DOHC means the engine has an seperate camshaft for exhaust and intake as opposed to just one, wouldn't be causing the sound. VTEC makes the changeover sound as when you hit a certain RPM a larger lobe on the intake cam is engaged...no idea what the noise you're hearing is mate! But if it sounds nice, enjoy it! lol
Stainless will eventually crack; even if it is well braced. Mild steel is stronger and less prone to cracking but the inside of the runners could rust and bits fall into the turbo BUT if I had to buy a mani, it would be mild steel as you don't have to worry about it cracking and can heat wrap it safely AND If I had lots of money to spend I would buy a race coated mild steel mani - like SPS sell.
HDI have a good route but I think the core is way too thick, its like 5 inches thick! If you can get a 2nd hand WEPR one I'd say get it. Good piping route, good sized core, high quality - good bits of kit, I regret selling mine!
Thats kinda the fun of BW meets. Turn up, have no idea where youre supposed to be going, keep an eye out for another Starlet and follow them. Happens to me everytime. lol
Its just that a lot of insurance companies (for some reason) don't list the Glanza. So it makes it harder to find a good deal as the majority of companies will say they can't insure a Glanza (and if they do they will insure it as a facelift GT Turbo etc.)