i don't know why you would have to destroy a tank to glow the coils. ???
i can't speak to the TPP RBA but the PnP one is very small, which means small, simple coils are all you can get in there. Voopoo sells, or sold, pre-built coils for the PnP RBA in a container of 10.
Is it worth it? If you really love a PnP tank you've got, sure. You just have to deal w/ the tiny size. Otherwise, a decent RTA would be a lot easier to work with, imo, and let you use complex coils.