The 22" increase in length will be welcome,the 420/430 was very tippy with the front end loader or 60/72" deck trying to go downhill and lift the deck for obstructions...i just hope it isnt at the expense of agility because thats one area the 420/430 really shined,they were good in tight spaces,and for getting around trees,especially the older 420s ,before they pulled oil from the rear diff,they steered really tight,the newer 420s had a hard oil pickup line running from the main pump to the rear axle in the way,it limited how tight they turned.I have 1 of each,the old one is a much better trim mower...As for the diesel, i think what it comes down too is space for the engine,with the way they set the engines backwards on the steiners and ventracs the cooling system is right behind the operator controls,and the pto drive needs to be where it is...I tried fitting my kubota d1105 in my ventrac..its 4" too long,simply wont fit without moving radiator rearward or losing cooling fan,neither which are possible...the 31 Briggs Diahatsu gas or diesel is a very compact engine,only 15" long,which is probably why they are the only LC engines in use in them....The Steiners have the same amount of room,so nothing bigger than the 950 will fit in the new tractor...the 430 only could get the d721 in there...not even close to big enough.