ME1 Weapon Comparison

The “damage” stat on the weapons in the first Mass Effect game is actually the damage per second (DPS) stat.

Therefore, we can compare all the weapons types in terms of their base DPS. The following is the DPS on the highest rank of Spectre weapons:

HMWA X (Assault rifle): 384 DPS

HMWSG X (Shotgun): 378 DPS

HMWSR X (Sniper rifle): 336 DPS

HMWP X (Pistol): 294 DPS

With no skills, the assault rifle (AR) has the highest DPS. But, the pistol's marksman ability (unlocked through the pistol talent) increases the rate of fire of the pistol for its duration. Master Marksman (12 points in pistol talent) increases the rate of fire by 2 rounds per sec. Without marksman, pistols fire at about a rate of 4 rounds per second.

Thus, the DPS of the pistol with Master Marksman is,  294 * 6/4 = 441 DPS. This is higher than the AR's DPS. If you can keep Master Marksman activated 100% of the time, it will certainly do more damage over time than the AR. 

Therefore, including marksman the DPS chart becomes:

HMWP X (Pistol) with Master Marksman: 441 DPS

HMWP X (Pistol) with Advanced Marksman: 404 DPS

HMWA X (Assault rifle): 384 DPS

HMWSG X(Shotgun): 378 DPS

HMWP X (Pistol) with Marksman: 368 DPS

HMWSR X (Sniper rifle): 336 DPS

HMWP X (Pistol): 294 DPS

Keep in mind that the sniper rifle and shotgun can do more damage on their first shots with the Assassination and Carnage abilities. Depending how long you fire, they may have a higher DPS than the AR or pistol.

How to Turn Ashley Paragon

In a similar process to turning Kaidan renegade, Ashley can be changed to be "paragon" in the first Mass Effect game. However, she will change for the better by becoming less xenophobic and more open minding about aliens.

If you want to change Ashley, you must play as male Shepard and romance her. As usual, talk to her after every main mission and be kind to her.

Eventually, Ashley will offer to have a drink with her and tell the story about her grandfather surrendering at Shanxi. During this conversation, listen for when Ashley says, “But hey, maybe once we saved the galaxy the Alliance will get its act together. Start acting like an actual government.” Respond to this by picking the “Alliance is all right” (top right) option on the dialog wheel. On the following dialog wheel, you can pick any of the three options. After going through these two dialog wheels, charm and renegade options will open up. Pick the charm to turn Ashley paragon.

All that is left is to do is to take the romance to completion. When Ashley comes to Shepard's cabin to spend the night with him, she should make a comment, “I couldn't blame the Council for calling us reckless or aggressive”. This confirms that you have successfully changed Ashley.

How to Turn Kaidan Renegade

If you want to turn Kaidan "renegade" (make him xenophobic) in the first Mass Effect game, you must play as female Shepard. The reason being is that he can only be turned renegade during the romance path.

Romancing Kaidan is pretty simple. Talk to him after completing every main mission. Be kind to him, and be sure to tell him you're interested in him. If the topic of Liara comes up, do not tell him that you're romantically interested in her.

Also, keep in mind that you will need 5 points in charm or intimidate to ultimately be able to turn Kaidan.

Kaidan will eventually give a conversation which reveals that he killed Vyrnnus at Jump Zero. In this conversation, he will say, "So yeah, I hated that turian. But he wasn't a turian to me. He was Vrynnus." You need to respond to this with the "turians are all the same" (bottom right) dialog option. On the following dialog wheel, you want to pick "I'm not so sure" (bottom right). Picking these two bottom right options should open up charm and intimidate options (left side). You can pick either of these charm or intimidate options to successfully turn Kaidan renegade.

After completing another main mission, Kaidan will have a new conversation, and he should express an anti-alien view. Encourage him by picking bottom right dialog options. Do not pick any charm or intimidate options in this conversation if you see them because these will only undo the changes in Kaidan. 

You will know that you've successfully changed Kaidan when he rants about those "damned aliens" before the love cut scene.