Jennifer,
I just want to add, that what you are trying to do does seem a bit shocking, especially for a newbie to 240SX's and maybe even performance cars in general? (just my impression)
But I've also seen that many people who try something new are often critisized exactly like you were here and they end up actually pulling it off in quiet on their own and all the critics are silenced and amazed.
I only recommend that you consult with some experts about your TT conversion (on the KA or a SR). Either way it's going to be an expert only affair. I am also assuming that you have quite a bit of pocket change and time to spare. BTW, TT 240's do exist, and they aren't all RB or VG transplants. I've seen two turbo's (I don't think they were sequential) on a SR before (in pics). Each turbo attached to 2 exhaust ports. I don't think a turbo manifold like this exists to purchase, so unless you want to make it yourself or have another uncle that knows how, you need to have a custom pro-welder made thingie made. It's going to cost bucks, especially if you want show quality looks (like it seems you are going for).
Either reconsider, study more, or if you're certain about this, good luck to you. Can't wait to see the finished product. <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/smile.gif" border="0" valign="absmiddle" alt=':)'>