I have worked out some of the main riffs, but not the improv/solos. The song is mainly 
E minor (pentatonic) but does change at times to C# minor (again, pentatonic feel).

Intro - volume swell

|----------------------------------------------|
|--7h9p7h9-------------------------------------|
|--7h9p7h9 etc-----7/9~~~~~--------------------|
|----------------------------------------------|allow feedback
|------------------5/7~~~~~--------------------|
|----------------------------------------------|

Main riff
|----------------------------------------------|
|----------------------------------------------|
|----------------------------------------------|
|----------------7-6-------------------7b-5----|
|-------5--7---------7---------5-7----------7--|
|-0--7--------0----------0--7-------0----------|

|----------------------------------------------|
|--------------------------3~~~~~--------------|
|--------------------------2~~~~~--------------|
|---------------7-6--------0-------------------|X2
|-------5-7----------7-------------------------|
|-0--7-------0---------------------------------|

Riff 2
|----------------------------------------------|
|-2---3----5--5h6p5-3---2----3--5--------------|
|-1---2----4------------1----2--4--------------|
|-----0----2-----------------0--2--------------|
|-4---------------------4----------------------|
|----------------------------------------------|

Ending Riff
|-0--------------------------------------------|
|-0--------------------------------------------|
|-1---------9--------9---------6---------------|
|-2-----11-------11---------7------------------|
|-2---8--------9---------------------------7---|
|-0-----------------------7-------0---3/4------|
                             (not exact)
|----------------------------12---15b(17)-15------------------------|
|-------------------------12------------------15-12-----------------|
|-------9---------9---14b---------------------------14b--14--12-----|
|----11-------11------------------------------------------------14--|
|--8--------9-------------------------------------------------------|
|-------------------------------------------------------------------|

|----------------------------------------------|
|---------------------------------15~~~~~------|
|--------9--------9--------6-------------------|
|----11--------11--------7--------14~~~~~------|
|--8---------9---------------------------------|
|----------------------7------0----------------|
The last 2 notes played at the same time are not correct, I have no idea what they are. 
you watch the 1988 live version in Austin you will hear it.

|----------------------------------------------|
|----------------------------------------------|
|--------9--------9--------6-------------------|
|----11--------11--------7---------------------|
|--8---------9---------------------------------|
|----------------------7------0----------------|

|------------------------------------------------------|
|--------17--19-19-17--19~--------17-19-19b-19b------17|
|-16-18---------------------16-18---------------18-----|
|------------------------------------------------------|
|------------------------------------------------------|
|------------------------------------------------------|
I don't know the rest, it's basically a shred fest.

Then back to the riff...

|-------------------------------------------------|
|-------------------------------------------------|
|--------9--------7b(9)~~~----6-------------------|
|----11--------11-----------7---------------------|
|--8---------9------------------------------------|
|-------------------------7------0----------------|

|------------------------0---------------------|
|-------------------5----0---------------------|
|-------9--------9--6----1---------------------|
|---11--------11----7----2---------------------|
|-8---------9------------2---------------------|
|-------------------7----0---------------------|