Introduction to fellow GWOA members

Hi Members. 

By profession I work as an Architect and am married with 2 children. I have a passion for Classic cars and have both a W123 and a W114 (Coupes) as part of my collection. 

I've recently joined the GWOA in the hope that I can get a better insight into the G Wagon range. I purchased a 1992, 300GD LWB and whilst the car is in exceptional condition for its age, I would like some advise on possibly increasing its torque or bhp. I am not a boy racer (those days are long gone) but would like a little more power when needed. Can anyone suggest a solution (a change of engine is not an option) although I may consider a Turbo version in the future. I have read up on the subject but it's all a bit too confusing as I am told its not really possible to do anything with a Non-Turbo engine. Current bhp on the 300Gd is 113bhp. I've recently had the car serviced with all new Filters including replacing the Injectors. 

I live in Cheshire and whilst I have some leads I would prefer to take advise from fellow GWOA members and any suggestions would be greatly appreciated. 

Afaq