[asperformance]

the timing tensioner is simply a bolted on plate that can be swapped or re-used depending on what you wnat to do...........
in terms of engine spec it would all depend on what power target or mods you were planning (if any?) as the original hydraulic tappet heads can be problematic and are best replaced with the later MY97/98 solid shim type (ideally the v.rare STi under-bucket option)

later blocks can be used by playing with compression ratios / headgasket,. etc