I would not change much, it took me long enough to get my rifles right. Luckily I could experiment without the handicap of needing to keep my rifles to any original style, shape or cal. Of course I can constantly try out new things which is pure fun.
Possibly the best Improvement and one of my favourite hunting rifles is my Mauser 1909 that has an ultra light carbon fibre stock, Lothar Walther match grade sporter barrel, AI type 5 or ten shot mag in 308 and has the original 2 stage trigger which is a dream for hunting. After that I enjoy a light weight tactical (7.7lbs without scope) which has a bog standard remmy action, carbon fibre stock, 20" Bartlein Palma barrel and shoots well, out to ~ 1000yds.
Next up is a T3 which will be also a light weight tactical, with 308 20" lilja, carbon fibre stock.
A 223 is also on the list, action will be a remmy that is lying around.
I learned a lot by just doing, not all "doings" were a success.
edi