TAMIYA RTR XB or RTR XB PRO

I m newbie for playing 1/10 RC car. I m planing to buy a set Tamiya RTR RC car. I read their features  
b4. The old XB use TL-01 with Mech speed control. And new XB PRO use TT-01 with Ele Speed
Control.
MY question is ... is it too bad to use mach spped control? how bad?
can I upgrade it to ESC if i buy XB version. Also I 'd play it in the park more than smooth road. What parts you guys recommend to upgrrade (based on TL01 and TT01)?  Does it really need to upgrade to ESC? ThanKs.

XB:
Specifications
Chassis Type: TL-01
Scale: 1/10
Length: 17.36 inches (441mm)
Width: 7.28 inches (185mm)
Wheelbase: 10.12 inches (257mm)
Front Tread: 6.18 inches (157mm)
Rear Tread: 6.18 inches (157mm)
Weight: 2.29 lbs. (1038g)
Chassis: ABS Monocoque
Suspension: 4 Wheel Independent
Damper Type: Plastic coil over friction
Drive Train: 4WD shaft drive
Gear Ratio: 7:96:1
Differential Gear System F/R: 3-Bevel Diff
Differential Type: Bevel Gear
Engine: Electric 540
Transmission Type: Shaft drive mid-ship full-time 4WD
Steering Tie Rod: 2 part
Speed Controller: 3 Step F&R Mechanical
Wheels & Tires: Spoke/radial
Tire Diameter F/R: both 64mm
Tire Width F/R: both 27mm
Body Type: Polycarbonate Cut & Printed

Radio: 2-Channel Pistol (included)
Power Source: 7.2V battery (not included)


XB PRo:
Chassis Type: TT-01
Scale: 1/10
Length: 17.36 inches (441mm)
Width: 7.28 inches (185mm)
Wheelbase: 10.12 inches (257mm)
Front Tread: 6.18 inches (157mm)
Rear Tread: 6.18 inches (157mm)
Weight: 3.46 lbs. (1570g)
Chassis: ABS Tub
Suspension: 4 Wheel Independent
Damper Type: Plastic coil over friction
Drive Train: Shaft drive
Gear Ratio: 8.35:1
Differential Type: Bevel Gear
Engine: Electric 540
Speed Controller: Electronic Speed Controller (CPR Unit)
Wheels & Tires: 10 Spoke/Radial
Body Type: Polycarbonate Cut & Printed
Caster Angle-F/R: 2deg/0deg
Camber Angle-F/R: 1deg/1deg
Toe Angle-F/R: 0deg/0deg
Differential Gear System: F/R 3-Bevel Diff
Tire Width: F/R both 27mm
Tire Diameter: F/R both 65mm
Tread Pattern: F/R Radial Type
Radio: 2-Channel Pistol (included)
Power Source: 7.2V battery (not included)

xb pro uses better controller as well.

最好就買kit la...