Don't sell, claim or guarantee to be able to do anything. It can be simply written but needs some special attention focused on certain parameters.
The concerned authority should drive home the purpose of the letter and correspond, if the request mentioned in the letter could be considered. It is useful to suggest or state that your company is 'the only' company able to do whatever you are claiming.
Given that most introductory letters avoid mentioning prices many decision-makers find it refreshingly 'up front' and honest - no nonsense - to see clear early indication of financials - if only as a guide.
People read by recognising word-shapes not individual letters, so don't use upper case anywhere, as it takes longer to read and reduces impact.
It also shows that you have a professional appreciation of the value of people's time. Think how you treat unsolicited letters that you receive. Make the letter an ad hoc endeavor to make the intent of your letter known.
In case, you are interested to know anything about our firm, feel free to contact on the address and contact details given in the brochure. Amidst all the junk mail, a personally worded letter with an original signature on good stationery can make a great impression.
Subject: New business, new deal Dear Mr.
Sign your letter.