some scaffold tube & plastic drain pipe will probably improve it :lol:
Assuming the engine is stock & you want to keep your heat exchangers then there are a few choices either stock type in either stainless or mild steel e.g
a stock jobby from GSF with some hefty amounts of heat proof paint splashed on will be cheapest, or bluebird to a stainless stock style beetle one that can be made to fit.
or a 4 into 1 header with some sort of box attached - millions of choices here however again something stainless will last - these can be bought from all the ususal places with JK, Bluebird, VWSpeedshop, doing bus specific stuff or my personal favourite - custom made by http://www.turbothomas.com" onclick="window.open(this.href);return false;.
It all comes down to how much you want to spend & how long you plan on keeping it really.